Do Diets Work?
Are Weight Loss Programs Effective?

A Review of The Research
Do weight loss programs like Noom, Weight Watchers, Jenny Craig and others work? The science says no.
This is a long, heavily researched article with links to supporting studies so you can check out the research for yourselves.
If you want to skip right to the conclusion, here it is: Even the best weight loss programs fail to deliver long-term, sustained weight loss.
The latest systematic review (summarizing individual studies) examined the effects of 14 popular diet programs, and found that none of them worked in the long term.
None.
Not some. None.
Every program took dieters on the same journey: initial weight loss followed by slow weight gain. By the end of 12 months almost everybody gained the weight (and many ended up weighing more than when they first started the diet).
You'd think that some weight loss programs would be better than others but the study found there weren't any significant differences between the 14 popular diet programs they studied.
Despite their various approaches and differing levels of medical or commercial involvement, they all had similar results in terms of effectiveness over time. That is, that they failed to produce weight loss in the long-term.
This calls into question the sustainability of these diets, and highlights the need for more research on long-term weight management strategies.
It also serves as a reminder that while quick fix diets might offer initial results, lasting changes often require a more holistic approach that addresses both physical and psychological aspects of eating habits.
Only three programs address these issues and they both have the research to back up their claims to success. Neither is a diet per se, as they do not give advice on what to eat or avoid.
The first is
Intuitive Eating. The other is
Neuroslim. Oh, and of course,
Mindful Eating. But we digress...
Let's examine why diets and weight loss programs are such dismal failures:
How Science Explains Why Diets Fail
Studies on Dieting's Effectiveness
Dieting Decreases Satiety Hormones
Dieting Compels You To Overeat
Dieting Is Bad For Your Mental Health
INTRODUCTION
Not long ago a landmark study provided evidence that our bodies resist dieting with fat-promoting biological responses. Dr. Rudolph L. Leibel, co-discoverer of leptin (“the satiety hormone”), found that dieting triggers signals from the brain to increase hunger and slow metabolism.
Follow-up studies replicated Dr. Leibel’s results and it wasn’t long before a scientific consensus formed: The body responds to dieting with a fight or flight syndrome, producing unwelcome physiological responses that cause weight gain.
What exactly sets off your body’s fight or flight response? Food scarcity and/or food insecurity. Your body cannot tell whether it’s starving because you’re dieting or because food disappeared from the savannah. It goes into survival mode by slowing metabolism (to conserve energy) and increasing hunger (to motivate you to find food).
The harder you try to lose weight the harder your body fights back. Dr. Leibel’s research showed that dieting can slow your metabolism by 15%. This explains a common dieting experience: You lose weight quickly and then slowly gain it back even though you’re sticking to the diet.
Why Diets Don't Work
This is the quandary that all dieters face: the very act of dieting creates an unequal and overwhelming force opposing it.
Dieting isn’t good for our mental health either. First, deprivation causes anxiety and depression. Counting calories, measuring food, weighing portions, and standing sentry 24/7 to monitor all intake is exhausting, debilitating, and demoralizing.
And that’s during the diet. After the diet fails (95% of the time), a whole other round of self-abuse begins. We take personal responsibility for the failure despite the fact we have no control over the autonomic responses that slow down our metabolism and dysregulate hunger and satiety hormones.
We don’t blame the body’s fight or flight response; we blame ourselves. We’re weak, we have no will power, no discipline, and no grit. Our self-esteem plunges, our confidence evaporates and we stew in an ugly puddle of feels.
Dieting Doesn't Work
Dieting is a danger to our mental health and our physical well-being. It's why the anti-diet culture took off. But let's do a deep dive of what the science says happens to your body when you go on a diet.
Does Dieting Work?
A Scientific Inquiry
In a study published in Obesity: A Journal, clinical researchers working in both medical and university centers, report that the overwhelming evidence shows diets do not work in the long term. A deep-dive analysis of extensive clinical studies reveal that, in general, the majority of people who follow strict restrictive diets end up gaining weight over the long term.
The researchers performed a meta-analysis of results from longitudinal studies on results from “energy restricted diets” and the frequency of “observed weight regain” afterward. To qualify for analysis, each study had to have “a minimum follow-up duration of three or more years” and include a minimum of 50 participants.
Most of the studies “prescribed diet in combination with exercise advice and/or a form of behavioral therapy.” They excluded papers that included alternate weight loss measures such as bariatric surgery or contained too few participants with only short-term follow-up.
In addition, “a random-effects meta-analysis for weight loss difference was done for those studies in which diet intervention was compared to a control group.” The researchers found that “weight regain after initial weight loss [was] observed in the majority” of participants in all of the studies. Indeed, “a substantial part of participants end up significantly heavier than before the intervention”—i.e., dieting.
The researchers conclude that when clinicians prescribe “a diet for the treatment of obesity, health practitioners should discuss with their patients that this intervention is only useful if permanent dietary changes are made.”
A similar review of studies reported in the Nutrition & Dietetics Journal of Dietitians Australia, showed that while “very low-energy diets” result in initial weight loss, that “initial weight loss is [not] maintained long-term.”
The paper concludes that “future studies using very low-energy diets” should be carefully analyzed to determine if the goal is “long-term weight loss in adults.” This is, of course, an interesting distinction because anecdotal evidence shows almost everyone seeking to lose weight desires a long-term solution.
Does Dieting Make You Fat In The Long Run?
In a more medically-focused report published in Circulation: Cardiovascular Quality and Outcomes, medical researchers also found that while diets tend to work in the short-term , they are not necessarily helpful for the long-term.
The study, “Long-Term Effects of Four Popular Diets on Weight Loss and Cardiovascular Risk Factors: A Systematic Review of Randomized Controlled Trials,” focused on determining the efficacy of popular diets such as “Atkins, South Beach, Weight Watchers, and Zone diets.”
Participants all achieved “modest” weight loss, but “24-month data suggest that weight loss…is partially regained over time.” The researchers also point out that “despite millions of dollars spent on popular commercial diets, data are conflicting and insufficient to identify one popular diet as being more beneficial than the others.”
Is Dieting Effective?
That is clinical-speak for none of them work all that well for the long-term, though in the short-term, all of them did result in some weight-loss and some reduction on cardiovascular risk factors. The problem is that most participants gained the weight back and—presumably—increased their cardiovascular risk factors.
None of the studies addressed the long-term effects on the cardiovascular system of a lifetime of yo-yo dieting—losing weight then regaining it, again and again. The researchers in all of the papers hedged their bets by suggesting that “more studies” are necessary to get clearer information on effective long-term solutions.
Studies reviewed:
Langeveld, M., & DeVries, J. H. (2015). The long-term effect of energy restricted diets for treating obesity. Obesity (Silver Spring, Md.), 23(8), 1529–1538. https://doi.org/10.1002/oby.21146
Asher, R.C., Burrows, T.L. and Collins, C.E. (2013), Very low-energy diets for weight loss in adults: A review. Nutrition & Dietetics, 70: 101-112. https://doi.org/10.1111/j.1747-0080.2012.01628.x
Atallah, R., Filion, K. B., Wakil, S. M., Genest, J., Joseph, L., Poirier, P., Rinfret, S., Schiffrin, E. L., & Eisenberg, M. J. (2014). Long-term effects of 4 popular diets on weight loss and cardiovascular risk factors: a systematic review of randomized controlled trials. Circulation. Cardiovascular quality and outcomes, 7(6), 815–827. https://doi.org/10.1161/CIRCOUTCOMES.113.000723
DIETING INCREASES HUNGER
Ghrelin is a hormone secreted primarily by the stomach that serves as a signal for the brain to regulate appetite and food intake. Its serum levels rise when you’re fasting or waiting for food.
Ghrelin stimulates the brain to make you feel hungry, and then they drop during and after the end of the meal and then other hormones get produced that make you feel full.
In addition to its role in appetite, it has several other functions in the body including an effect on stomach acidity and motility, growth hormone production, heart function, bone strength , blood sugar, nervous system function, and lipid storage. Its role in the latter is also interesting to look at.
Ghrelin stimulates fat storage enzymes, reduces the usage of fats and increases blood triglyceride levels[1]. In other words, if for any reason your stomach started to make more ghrelin, overtime your body is going to accumulate more fat.
Another Reason Why Diets Don't Work
One thing that has been shown to increase blood ghrelin levels is dieting, which makes sense. When you’re on a diet and you’re chronically restricting your food intake, your stomach sends a signal to the brain by producing ghrelin.
Your brain doesn’t know that you’re intentionally on a diet. So as far as it’s concerned, you should eat more to keep you from starving, so it makes you feel hungrier and you have to fight the need to overeat.
A study was conducted on 60 women with obesity, where they were randomized to either go on a fasting-mimicking diet for 5 days, which consists of low energy, sugars and proteins but high unsaturated fats, or on a continuous energy restriction for 2 months, which consists of an average energy deficit of 500 kcal.
By the end of the study, the researchers found that the continuous energy restriction group had significantly increased total ghrelin and neuropeptide Y levels [2].
Neuropeptide Y is secreted by a part of the brain called the hypothalamus in response to ghrelin from the digestive tract. It’s an important mediator for the function of ghrelin.
Another study was conducted on 38 normal-weight healthy women. The participants were randomized to four groups: A control group that was given a diet with just enough calories to maintain their initial weight, a group who exercised but was given enough calories to maintain their weight, a group who exercised and was given a moderate energy deficit diet, and a group who exercised and was given a high energy deficit diet.
The interventions lasted for 3 months, and 22 participants completed the study. When the researchers measured their ghrelin levels, they found that the group of participants who lost weight by exercising and going on a low-calorie diet had significantly higher ghrelin levels than the control group and the exercising group who maintained their initial weight [3].
An analysis of the same study by different researchers later showed that the change in ghrelin levels can be affected even by small changes in energy availability [4]. Another study was performed on 13 obese subjects who took a 6 month dietary program for weight loss.
They measured their weight and serum ghrelin levels before and after the study. For a weight loss of 17 percent, the area under the curve for their 24 hour ghrelin levels increased by 24 percent [5].
These results have also been demonstrated in non-human subjects. A study was conducted on 24 albino male rats that were randomized into 4 groups: a non-fasting control group, a control group fasting for 20 hours, a non-fasting low-fat diet group, and a low-diet group fasting for 20 hours. Their serum ghrelin levels were measured and showed that the low-fat diet fasting group had the highest ghrelin levels of all the groups [6].
This shows that whether the subjects are fasting and whether they’re on a diet both have an effect on ghrelin levels. Taken together, the results of these studies suggest that when you go on a diet, your body responds by increasing your serum ghrelin levels, which can lead to a stronger urge to overconsume in order to compensate the energy restriction. This could partially explain the high rates of relapse in diet-induced weight loss, and the difficulty to sustain a diet on the long-run [7].
Studies reviewed:
1. Ibrahim Abdalla M. M. (2015). Ghrelin - Physiological Functions and Regulation. European endocrinology, 11(2), 90–95.
https://doi.org/10.17925/EE.2015.11.02.90
2. Sadeghian, M., Hosseini, S. A., Zare Javid, A., Ahmadi Angali, K., & Mashkournia, A. (2021). Effect of Fasting-Mimicking Diet or Continuous Energy Restriction on Weight Loss, Body Composition, and Appetite-Regulating Hormones Among Metabolically Healthy Women with Obesity: a Randomized Controlled, Parallel Trial. Obesity surgery, 31(5), 2030–2039.
https://doi.org/10.1007/s11695-020-05202-y
3. Leidy, H. J., Gardner, J. K., Frye, B. R., Snook, M. L., Schuchert, M. K., Richard, E. L., & Williams, N. I. (2004). Circulating ghrelin is sensitive to changes in body weight during a diet and exercise program in normal-weight young women. The Journal of clinical endocrinology and metabolism, 89(6), 2659–2664.
https://doi.org/10.1210/jc.2003-031471
4. Scheid, J. L., De Souza, M. J., Leidy, H. J., & Williams, N. I. (2011). Ghrelin but not peptide YY is related to change in body weight and energy availability. Medicine and science in sports and exercise, 43(11), 2063–2071. https://doi.org/10.1249/MSS.0b013e31821e52ab
5. Cummings, D. E., Weigle, D. S., Frayo, R. S., Breen, P. A., Ma, M. K., Dellinger, E. P., & Purnell, J. Q. (2002). Plasma ghrelin levels after diet-induced weight loss or gastric bypass surgery. The New England journal of medicine, 346(21), 1623–1630.
https://doi.org/10.1056/NEJMoa012908
6. Zwain, A., & Mohammed, H. Q. (2022). EFFECT OF 20-HOUR FASTING AND LOW FAT DIET ON GHRELIN HORMONE, GLUCOSE LEVEL AND LIVER FUNCTION IN ALBINO RATS MALE. Wiadomosci lekarskie (Warsaw, Poland : 1960), 75(4 pt 1), 798–802.
https://doi.org/10.36740/WLek202204109
7. Asher, R.C., Burrows, T.L. and Collins, C.E. (2013), Very low-energy diets for weight loss in adults: A review. Nutrition & Dietetics, 70: 101-112. https://doi.org/10.1111/j.1747-0080.2012.01628.x
Dieting Slows Metabolism
Diets have also been shown to reduce the resting metabolic rate (RMR) and slow down your metabolism. RMR is the number of calories that your body needs at resting state.
It varies from person to person, and is affected by age, gender and obesity [1]. Additionally, when you go on a diet to lose weight, your body adapts to the lack of energy by reducing your RMR, making you burn less calories than you normally do. This translates to a subsequent difficulty to maintain the weight you achieved.
A study was conducted on 48 healthy men and women. They were randomized into 1 of 4 groups to go on different diets for 6 months: a weight-maintenance diet for the control group, a 25% calorie restriction diet, a 12.5% calorie restriction diet with a structured exercise, or a very low calorie diet until 15% weight loss is achieved and then a weight-maintenance diet.
Another Case For No Dieting
After the study was completed, they found that for all but the control group, there was a significant amount of metabolic adaptation leading to a decrease in RMR in the first 3 months, that remained constant for the rest of the study [2][3]. This shows that a long-term calorie-restricted diet can slow down your metabolism during the first 3 months.
In another study, 71 participants with obesity were randomized to 1 of 3 groups, each group receiving a different type of diet consisting of 1000 kcal/day for 8 weeks.
By the end of the study, resting metabolic rate of the participants was significantly lower than predicted, demonstrating the presence of a metabolic adaptation even for just 8 weeks of a calorie-restricted diet [4].
An observational study looked at 14 participants in “The Biggest Loser” competition to see how their body composition and RMR changed over 6 years after the competition.
Initially, they lost an average of 58.3kg, that’s 128.5 lbs. After 6 years, they regained an average of 41kg of it, that’s 90.3 lbs. If we do the math, the participants regained approximately 70% of the weight they lost. They also found that their RMR was decreased after the competition and was even lower after 6 years [5].
A meta-analysis examined the studies comparing formerly obese subjects to a group that has never been obese, and found that although they’re currently not obese, their RMR was 3-5% lower than the control group [6]. Showing that the decrease in RMR persists for a long time after weight loss, and can make a formerly obese individual at risk of regaining the weight they lost.
The results from these studies suggest that: 1) Dieting can reduce RMR. 2) the rate of reduction and the time it takes can depend on the degree of energy restriction and the rate of weight loss. 3) RMR can remain low for a long time after weight loss. 4) It can make it difficult to maintain the new weight, as the body burns less calories than it used to.
We’re not talking about a small percentage of weight regain. As we saw in the results of the observational study, the competitors regained approximately 70% of the weight they lost during the competition [5].
Another study on 57 overweight and obese subjects found that participants regained approximately half of the weight they lost after a dietary intervention program [7].
This raises questions on whether dieting is a good way to lose weight considering that there’s a high risk of relapse, even after the desired weight is achieved. This is possibly due to multiple factors.
As we discussed earlier, diets can cause an increase in the hunger hormone ghrelin and a decrease in the satiety hormone leptin, making you crave more food than if you didn’t go on a diet. In association with the metabolic adaptation effect and possibly other factors, they can explain the high rate of weight regain after diet-induced weight loss.
References:
1. McMurray, R. G., Soares, J., Caspersen, C. J., & McCurdy, T. (2014). Examining variations of resting metabolic rate of adults: a public health perspective. Medicine and science in sports and exercise, 46(7), 1352–1358. https://doi.org/10.1249/MSS.0000000000000232
2. Heilbronn, L. K., de Jonge, L., Frisard, M. I., DeLany, J. P., Larson-Meyer, D. E., Rood, J., Nguyen, T., Martin, C. K., Volaufova, J., Most, M. M., Greenway, F. L., Smith, S. R., Deutsch, W. A., Williamson, D. A., Ravussin, E., & Pennington CALERIE Team (2006). Effect of 6-month calorie restriction on biomarkers of longevity, metabolic adaptation, and oxidative stress in overweight individuals: a randomized controlled trial. JAMA, 295(13), 1539–1548. https://doi.org/10.1001/jama.295.13.1539
3. Martin, C. K., Heilbronn, L. K., de Jonge, L., DeLany, J. P., Volaufova, J., Anton, S. D., Redman, L. M., Smith, S. R., & Ravussin, E. (2007). Effect of calorie restriction on resting metabolic rate and spontaneous physical activity. Obesity (Silver Spring, Md.), 15(12), 2964–2973. https://doi.org/10.1038/oby.2007.354
4. Martins, C., Roekenes, J., Gower, B. A., & Hunter, G. R. (2021). Metabolic adaptation is associated with less weight and fat mass loss in response to low-energy diets. Nutrition & metabolism, 18(1), 60. https://doi.org/10.1186/s12986-021-00587-8
5. Fothergill, E., Guo, J., Howard, L., Kerns, J. C., Knuth, N. D., Brychta, R., Chen, K. Y., Skarulis, M. C., Walter, M., Walter, P. J., & Hall, K. D. (2016). Persistent metabolic adaptation 6 years after "The Biggest Loser" competition. Obesity (Silver Spring, Md.), 24(8), 1612–1619. https://doi.org/10.1002/oby.21538
6. Astrup, A., Gøtzsche, P. C., van de Werken, K., Ranneries, C., Toubro, S., Raben, A., & Buemann, B. (1999). Meta-analysis of resting metabolic rate in formerly obese subjects. The American journal of clinical nutrition, 69(6), 1117–1122. https://doi.org/10.1093/ajcn/69.6.1117
7. Muhammad, H., Vink, R. G., Roumans, N., Arkenbosch, L., Mariman, E. C., & van Baak, M. A. (2017). Dietary Intake after Weight Loss and the Risk of Weight Regain: Macronutrient Composition and Inflammatory Properties of the Diet. Nutrients, 9(11), 1205.
https://doi.org/10.3390/nu9111205
DIETING DECREASES SATIETY HORMONES
(It's Harder To Feel Full)
In contrast with the function of ghrelin, leptin induces the sensation of satiety. It’s a hormone produced by our fatty tissue in response to food intake and released into the bloodstream. It travels to the brainstem and hypothalamus where it stimulates the production of substances that block your appetite, and inhibits substances that increase your appetite. It's known as the ‘satiety hormone’ [1].
While ghrelin production increases when you’re fasting and decreases after meals, leptin production decreases when you’re fasting and increases after meals. When leptin rises, it tells your brain that you’re not hungry anymore, but it doesn’t stop at appetite inhibition. It’s also involved in the regulation of energy use by the body.
Such that when leptin is low, the brain thinks that we’re in a state of starvation and that we need to eat more and save the energy stores in the body from being consumed. It does that by affecting lipid and sugar metabolism as well as thyroid, reproductive and growth hormone synthesis.
When leptin increases, the body bounces back from energy-saving mode, puts a brake on food intake, and promotes energy use [2][3][4]. Anything that modifies leptin production can therefore have an effect on these physiological and behavioral processes.
Another Reason Why Dieting Doesn't Work
In addition to their effect on ghrelin, diets have been shown to reduce serum leptin levels. A systematic review of clinical trials looked into the studies that investigated the effect of fasting and energy-restricted diets on serum leptin levels.
They found 12 relevant studies and then analyzed their results statistically in a meta-analysis. They found that the studies together suggest a significant decrease in leptin levels during fasting and energy-restricted diets [5].
A study was conducted on 10 obese males and females. They took a 6 month weight-loss program consisting of a diet in association with physical activity. The researchers measured their leptin levels and free leptin index in the end of the trial.
They found that both were significantly reduced after 6 months of dietary and exercise interventions [6]. Free leptin index is an indicator for leptin sensitivity. Which means that a low free leptin index suggests a resistance of the body towards leptin [7].
Therefore, this study demonstrates that diets can reduce not only serum leptin levels, but also the biological function of the leptin that’s present.
A study aimed to determine if a decrease in leptin is responsible for a weight regain after a weight-loss intervention. Four obese subjects were given a liquid diet that changed composition for different stages of the study.
The first stage, they were given enough calories to remain at their initial weight. At the second stage, they received enough calories to maintain a 10% reduction of their body weight. At the final stage of the study, they continued to receive a diet that kept them at the 10% weight reduction, along with injections of human recombinant leptin that achieved similar leptin levels throughout the day as when they were in their initial weight.
Serum leptin and thyroid hormone levels were measured several times during the study and were shown to be reduced at the second stage, and restored at the third stage of the study [8]. Thyroid hormone reduction is an indicator of the metabolism slowing down and reduction in energy expenditure [9].
These results show that because leptin is reduced during a low-calorie diet, the body adapts by saving energy, and that can lead to a partial regain of the lost weight. The reversibility of these effects by the administration of injectable leptin proves the relationship between leptin and weight regain that is associated with diet-induced weight loss [10].
These studies demonstrate that dieting reduces plasma leptin levels, that it increases the body’s resistance to leptin by reducing free leptin index, and that similarly to the ghrelin increase during dieting, leptin reduction can have an effect on increased food intake and weight regain after diet-induced weight loss.
References:
1. Klok, M. D., Jakobsdottir, S., & Drent, M. L. (2007). The role of leptin and ghrelin in the regulation of food intake and body weight in humans: a review. Obesity reviews : an official journal of the International Association for the Study of Obesity, 8(1), 21–34.
https://doi.org/10.1111/j.1467-789X.2006.00270.x
2. Flak, J. N., & Myers, M. G., Jr (2016). Minireview: CNS Mechanisms of Leptin Action. Molecular endocrinology (Baltimore, Md.), 30(1), 3–12.
https://doi.org/10.1210/me.2015-1232
3. Allison, M. B., & Myers, M. G., Jr (2014). 20 years of leptin: connecting leptin signaling to biological function. The Journal of endocrinology, 223(1), T25–T35.
https://doi.org/10.1530/JOE-14-0404
4. Dornbush S, Aeddula NR. Physiology, Leptin. [Updated 2022 Apr 14]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2022 Jan-. Available from:
https://www.ncbi.nlm.nih.gov/books/NBK537038/
5. Varkaneh Kord, H., M Tinsley, G., O Santos, H., Zand, H., Nazary, A., Fatahi, S., Mokhtari, Z., Salehi-Sahlabadi, A., Tan, S. C., Rahmani, J., Gaman, M. A., Sathian, B., Sadeghi, A., Hatami, B., Soltanieh, S., Aghamiri, S., Bawadi, H., & Hekmatdoost, A. (2021). The influence of fasting and energy-restricted diets on leptin and adiponectin levels in humans: A systematic review and meta-analysis. Clinical nutrition (Edinburgh, Scotland), 40(4), 1811–1821.
https://doi.org/10.1016/j.clnu.2020.10.034
6. Herrick, J. E., Panza, G. S., & Gollie, J. M. (2016). Leptin, Leptin Soluble Receptor, and the Free Leptin Index following a Diet and Physical Activity Lifestyle Intervention in Obese Males and Females. Journal of obesity, 2016, 8375828.
https://doi.org/10.1155/2016/8375828
7. Donoso, M. A., Muñoz-Calvo, M. T., Barrios, V., Martínez, G., Hawkins, F., & Argente, J. (2013). Increased leptin/adiponectin ratio and free leptin index are markers of insulin resistance in obese girls during pubertal development. Hormone research in paediatrics, 80(5), 363–370.
https://doi.org/10.1159/000356046
8. Rosenbaum, M., Murphy, E. M., Heymsfield, S. B., Matthews, D. E., & Leibel, R. L. (2002). Low dose leptin administration reverses effects of sustained weight-reduction on energy expenditure and circulating concentrations of thyroid hormones. The Journal of clinical endocrinology and metabolism, 87(5), 2391–2394.
https://doi.org/10.1210/jcem.87.5.8628
9. Danforth, E., Jr, & Burger, A. (1984). The role of thyroid hormones in the control of energy expenditure. Clinics in endocrinology and metabolism, 13(3), 581–595.
https://doi.org/10.1016/s0300-595x(84)80039-0
10. Ahima R. S. (2008). Revisiting leptin's role in obesity and weight loss. The Journal of clinical investigation, 118(7), 2380–2383. https://doi.org/10.1172/JCI36284
Dieting Incentivizes Overeating
Dieting creates a biological imperative to eat. It kicks off numerous biological adaptations designed to ensure your survival through what the body perceives on a cellular level to be an “emergency”—famine. This unconscious process is automatic and a holdover from humanity’s earliest hominid days when death by starvation was a very real possibility.
A millennium later, why do our bodies continue to do this? In the journal, Behavioral and Brain Sciences, researchers at Cambridge University propose the “insurance hypothesis” as one of the main reasons. The insurance hypothesis (IH) is “rooted in adaptive evolutionary thinking: the function of storing fat is to provide a buffer against shortfall in the food supply. Thus individuals should store more fat when they receive cues that access to food is uncertain.”
"Can I Lose Weight By Dieting?" NO.
In other words, our bodies are wired for survival and these wires were “laid down” during humanity’s earliest days of development. No amount of “thinking” or reasoning can “talk” our bodies into believing a sudden drop in calories is anything but a dire emergency where our very survival is at stake.
Interestingly, we are not the only species that reacts in this way to a sudden drop in calories consumed. The Cambridge study included studies “from non-human animals showing that fat reserves increase when access to food is restricted.”
Think bears eating as much as they can to store as much fat as possible before hibernation. What seems like a binge to us looks like smart planning to our ‘inner bear.” “Storage of body fat is an adaptive strategy used by many vertebrates, including humans, to buffer themselves against periods during which food is unavailable,” the study points out.
How much fat we store is dependent on “security of access to food: If food is guaranteed to be always available, relatively little fat storage is necessary, but as the risk of temporary unavailability of food increases, the amount of fat the individual should optimally store also increases.”
Over evolutionary time, our bodies learned to pick up cues that indicated food might suddenly become scarce. “Exposure to these cues engages evolved decision-making mechanisms and leads to increased food consumption relative to expenditure, thus resulting in greater fat storage and higher body weights.”
In other words, it’s a process/decision your body makes without conscious thought. It is automatic. You cannot override it because the biological imperative to survive is much older and more primal than humanity’s neo-cortex (frontal lobes, where we do most of our thinking).
It is a kind of evolutionary mismatch—we live in a world of abundance but our primitive brains are on constant alert for the next drought or flood or famine that might endanger us. “Obesity in contemporary populations is thus the by-product of a mind evolved to deal with frequent scarcity living now in constant abundance.”
We can blame evolution and our fat cells, it seems. “Specialized lipid stores are found in the bodies of all well-nourished animals,” the researchers point out. And “lipid storage is an evolved adaptation that allows individuals to continue to survive and reproduce in the face of temporary shortfalls in energy intake from food.” The more fat we store, the better prepared we are for “energy shortfalls,” the researchers point out.
Here is where dieting complicates matters. “If there is no risk of [food] shortfall, the individual can maintain a minimal level of fat and need not incur the drawbacks of carrying any more than that. If the risk of shortfall is substantial, then the individual has to carry fat as insurance—insurance that is to be paid in terms of the drawbacks of increased body weight.”
In other words, if there is food insecurity, our bodies will hold onto fat and increased weight as “insurance” against catastrophic starvation. The problem is that the body cannot tell the difference between a slow-down of food by choice and a slow-down of food by circumstances beyond our control. The researchers also point to studies that “showed that bird species whose winter food supplies were unpredictable…[insecure] carried more fat than those whose winter food supply was predictable (secure).”
This led to an understanding that “fat storage was plastic within individuals and could be deployed strategically as a response to environmental experience.” But again, no amount of cognitive understand could override the biological imperative to survive. As the researchers point out, understanding the insurance hypothesis “does not in itself change this situation…[but] it ought to change our framing of the problem.” The psychological mechanisms that ensured our survival throughout history cannot be countered by “simple information giving, food labeling, or explicit exhortation to override them.” They go on to state that restrictive dieting is likely “counterproductive.”
An article in the British Journal of Nutrition comes to the same conclusion: “Baseline dieting or dietary restraint increases the risk of weight gain, especially in women.” They point out that restrictive dieting has “also been implicated in the development and persistence of binge eating.”
A report in the International Journal of Behavioral Medicine comes to the same conclusion: “Dieting to lose weight can contribute to the risk of future obesity and weight gain.” Indeed the “odds of obesity were 1.9, 2.9, and 3.2 times higher among those who were on a diet once, more than once, and always, respectively.”
The bottom line: Dieting, particularly highly restrictive dieting, sets off a cascading series of biological imperatives that make it highly likely that your body will react with survival-based behaviors that result in weight-gain. As the researchers point out, “Dieting…contribute[s] to the risk of future obesity and weight gain.”
The techniques used in NeuroSlim are designed to change your habits without triggering the “insurance hypothesis” and biological imperatives that have contributed to your weight gain in the past. Dieting is not the answer. Changing your habits in pleasing, non-threatening ways through NeuroSlim is the long-term solution for permanent weight-loss.
Studies mentioned:
Nettle, D., Andrews, C., & Bateson, M. (2017). Food insecurity as a driver of obesity in humans: The insurance hypothesis. The Behavioral and brain sciences, 40, e105. https://doi.org/10.1017/S0140525X16000947
Siahpush, M., Tibbits, M., Shaikh, R. A., Singh, G. K., Sikora Kessler, A., & Huang, T. T. (2015). Dieting Increases the Likelihood of Subsequent Obesity and BMI Gain: Results from a Prospective Study of an Australian National Sample. International journal of behavioral medicine, 22(5), 662–671. https://doi.org/10.1007/s12529-015-9463-5
Hill, A. (2004). Does dieting make you fat? British Journal of Nutrition, 92(S1), S15-S18. https://doi.org/10.1079/BJN20041135
DIETING IS TOXIC TO MENTAL HEALTH
Multiple studies have shown that dieting does not work—that people who undergo intense “food restrictions” tend to gain back the weight they lost, plus some. It is not surprising then, that many other studies show that dieting causes mental and emotional distress as well.
For example, in the Journal of the Academy of Nutrition and Dietetics, researchers found that “starvation and self-imposed dieting appear to result in eating binges once food is available and in psychological manifestations such as preoccupation with food and eating, increased emotional responsiveness and dysphoria, and distractibility.”
Researchers' Favorite Words: "No Diet"
Researchers conclude that “caution is thus advisable” when it comes to recommending any kind of dieting or food restriction to patients in a health environment. That is basically “academic-ese,” for “don’t do it.” Instead, the paper concludes with the recommendation that “healthful, balanced eating without specific food restrictions” should be encouraged.
In the journal, Cureus, published via the California Institute of Behavioral Neurosciences and Psychology Channel, the researchers were more emphatic about their concerns over the link between dieting and psychological distress. In an article titled, “Have Our Attempts to Curb Obesity Done More Harm Than Good?” the researchers came to the same conclusions that “although dieting may cause short-term weight loss, it is associated with weight gain in the long-term.“ (See “Long-Term Studies Confirm: Diets Do Not Work,” here [link]).
They also found an abundance of studies showing “the negative psychological and physical outcomes of dieting.” They conclude that “dieting may carry more risks than benefits as a means to lose weight.”
The “harmful effects of dieting” can lead to eating disorders and other problems. “Numerous studies,” they discovered, “have shown the negative impacts of food restriction and dieting on psychological functioning.” Indeed, they concluded that “prolonged semi-starvation led to pronounced depression, emotional distress, and irritability.” Many were driven to binge-eating behaviors.
Those diagnosed with binge-eating disorders were more likely to be identified as obese. The authors of the paper point out that “female participants who dieted at a moderate level were five times more likely to develop an eating disorder….[while those] who dieted at a severe level were 18 times more likely to develop an eating disorder than those who did not.”
Eighteen times more likely! In one revealing portion of the paper, the authors wonder, “why do we continue to recommend dieting to patients?” Instead, they suggest “approaching obese patients holistically and with compassion…[and] recommend encouraging patients to adopt healthy attitudes toward eating instead of chasing after weight loss.”
Researchers report in Current Neuropharmacology, a surprising connection between dieting and antidepressant effectiveness. In the article, “The Effects of Calorie Restriction in Depression and Potential Mechanisms,” the authors point out a consistent percentage of patients who are resistant to “antidepressant therapies.”
Interestingly, they found that “the effects of calorie restriction in neuroendocrine system and in depression” were positive. In other words, for some patients, “short-term calorie restriction might induce an antidepressant efficacy in depression.” On a biological level, the short term restriction of calories activated a cascade of physiological processes that seemed to help make the antidepressants more effective. But again, only in the short-term.
As other studies have shown, severe calorie restriction often induces a rebound effect on eating and weight. The researchers did not comment on the efficacy of the antidepressants after normal eating resumed or weight was gained, so more research is required to determine what treatment efficacy after the period of caloric restriction. It does beg the question, though, whether there is an equal or more intense rebound effect on depression.
The American Psychological Association is concerned about the effects of dieting on mental health. In the journal, Health Psychology, the authors of “Consequences of Dieting to Lose Weight: Effects on Physical and Mental Health,” wonder whether “the negative physiological and psychological effects of dieting may outweigh aesthetic and health benefits.”
Their review of studies concludes that dieting’s connection to mental health is an “important unresolved issue.” Because of this unclear/unresolved aspect of the link between dieting and mental health, they recommend that weight loss only be encouraged only if “efforts involving moderate changes in eating and exercise habits” are encouraged.
In the article, “Association Between Diet and Symptoms of Anxiety and Depression in College Students: A Systematic Review” in the Journal of American College Health, researchers sought out “evidence on the association between diet and depression and anxiety among college students.” They looked at studies and articles published in multiple respected scientific publications over a ten-year period (2010-2020).
Their cross-sectional evaluations “found a positive association between diet and depression and anxiety.” By positive, they mean there was a connection or correlation. However, they also point out a “few studies found inconsistent results,” which means they are unable to un-equivocally say that dieting causes depression and anxiety, though there is evidence of a relationship. Part of the inconsistencies cited was that “consumption of fruit and vegetables improved depression” in some.
They point to a “pressing need to conduct more prospective, longitudinal, and randomized controlled trials to generalize the causal associates between diet and depression and anxiety,” and that “further research is needed to investigate the biological mechanisms of nutrients’ actions on anxiety and depression.”
Studies Cited:
Polivy J. (1996). Psychological consequences of food restriction. Journal of the American Dietetic Association, 96(6), 589–594. https://doi.org/10.1016/S0002-8223(96)00161-7
Memon, A. N., Gowda, A. S., Rallabhandi, B., Bidika, E., Fayyaz, H., Salib, M., & Cancarevic, I. (2020). Have Our Attempts to Curb Obesity Done More Harm Than Good?. Cureus, 12(9), e10275. https://doi.org/10.7759/cureus.10275
Zhang, Y., Liu, C., Zhao, Y., Zhang, X., Li, B., & Cui, R. (2015). The Effects of Calorie Restriction in Depression and Potential Mechanisms. Current Neuropharmacology, 13(4), 536–542. https://doi.org/10.2174/1570159x13666150326003852
French, S. A., & Jeffery, R. W. (1994). Consequences of dieting to lose weight: effects on physical and mental health. Health psychology : official journal of the Division of Health Psychology, American Psychological Association, 13(3), 195–212. https://doi.org/10.1037//0278-6133.13.3.195
Saha, S., Okafor, H., Biediger-Friedman, L., & Behnke, A. (2021). Association between diet and symptoms of anxiety and depression in college students: A systematic review. Journal of American college health : J of ACH, 1–11. Advance online publication.https://www.tandfonline.com/doi/abs/10.1080/07448481.2021.1926267?journalCode=vach20