The idea of “low-hanging fruit” describes something which may be obvious in hindsight which anyone could have discovered, or at least was easier than assumed, but for whatever reason no one noticed until it was pointed out. This elicits the reaction, “Oh…why didn’t I think of that?” Or in mathematics, the recent wave of AI-generated proofs has shown that some conjectures were not as intractable as previously thought. The actual difficulty was that mathematicians did not know where to look. AI has been able to resolve such impasses, as illustrated by the recent disproof of the Jacobian conjecture.
This leads to dieting and obesity. Why does dieting have such a high failure rate, and what can be done about it? To the answer the second question, GLP-1 drugs are highly effective, and better drugs are on the horizon. It’s possible obesity may be curable. But for the first question, the high failure rate of dieting is commonly blamed on “hyperpalatable foods,” “loss of willpower,” or, simply, “eating too much food”.
But, perhaps, the answer is in plain sight: “dieting frequently fails, not necessarily because of external or hormonal factors, but because the required daily number of calories to NOT be obese or overweight is surprisingly low for adults, way lower than thought and understandably not sustainable for the vast majority of people, hence 75% of the US population overweight or obese.”
This is corroborated by gastric bypass patients and GLP-1 users, who lose a lot of weight, but only after eating relatively few calories, typically only around 1,500 kcal/day as commonly reported by users. Sometimes even less–basically near starvation-level rations. This leads to concerns about nutritional deficiencies, bone weakness, and muscle loss, because this just isn’t much food. Yet this is what it takes to lose the necessary weight. The body is apparently that efficient. This extreme calorie restriction is only sustainable because the surgical procedure or drugs suppress hunger, along with other less well understood mechanisms of action.
Indeed, consulting Claude, GLP-1 users average 750–2,200 kcal/day. Gastric bypass patients: only 750–1,800 kcal/day. In my posts “Why the Minnesota Starvation Experiment Doesn’t Generalize to Modern Dieting” and “‘Slow Metabolism’ May Help Explain High Dieting Failure Rates,” successful long-term dieters of a national weight-loss registry (NWCR) averaged only 1,400 kcal/day to maintain a typical BMI between 23-25, the upper end of the range which is just under “overweight”:
The 1,400 kcal/day figure was corroborated by a 2012 study which divided a subset of NWCR subjects into four categories. All the categories consumed between 1,350–1,450 kcal/day on average. The most successful category, 3, had an average BMI of 23.3 and had maintained this lower weight for a mean of 133 months, making them outliers even among NWCR participants. Group 3 is also close to a 50–50 split between men and women, so optimistically, we can infer 1,200 kcal/day for women and 1,600 kcal/day for men.
This is well below the “official” 2,000 kcal/day stipulated by the FDA nutritional guidelines as a healthy diet for an adult. It’s much more likely that these people represent outliers who are able to tolerate so little food for so long, than something that can be reproduced at a national level. Good luck scaling this up for the entire country. Note, to clarify a common confusion, these low calorie figures are maintenance calories, meaning that for NWCR participants this is the number of daily calories to maintain their weight loss indefinitely, not to lose additional weight.
Does this mean metabolism does not matter? Not at all. Although it’s understood that slowed metabolism plays some role for regain (e.g. adaptive thermogenesis), as smaller people need fewer calories, the role of metabolism is greatly underappreciated for the high failure rate of dieting. Fast metabolism can also explain the ease of staying lean–as in under, say, 22 BMI–for a small percentage of population. Or the ability to cut weight in the context of modeling or fitness, and well into adulthood (as weight gain is common as people get older).
If someone’s natural/baseline RMR (resting metabolic rate) is higher, this means more room to cut calories to achieve a desired level of leanness. Like IQ or height, RMR and BMR (basal metabolic rate) are largely influenced by genetics, with RMR typically exceeding BMR by around 30%. Even activity does not raise RMR much, as corroborated by the aforenoted NWCR study, which showed that the most active participants had around the same low calorie intake (around 1,400 kcal/day, give or take 50) as the most sedentary participants.
Fast metabolism (“fast” in this content means relative to predicted metabolism for a person’s weight and height based on regression models), is as innate as IQ or height , with even more variability. My research on metabolism is much more dismal than commonly assumed. Basically, large segments of the population are in what can be described as a “permanent hibernation mode” of fat storage and energy sparing that is also impervious to exercise. This explains the absurdly low calorie requirements to merely not be overweight for these people, let alone lean.
In explaining the discrepancy between popular people on social media who are successful with dieting and have large followings, versus the “regular people” who fail when applying the same commonsense dieting advice (e.g. calorie calculators) commonly espoused by those popular people, selection effects are everything. As discussed in the post, “Bulking, Metabolism, and Selection Effects:”
As evidenced by how so many people are overweight or obese, most people have the opposite problem of storing fat too easily, even when not eating that much, whereas successful bodybuilders and fitness models/influencers may represent outliers whose bodies resist weight gain, requiring obscene quantities of food to get bigger compared to the typical overweight person who gains weight effortlessly and has to make a concerted effort to not get bigger.
Guys you see on social media who stay lean on high calorie counts (3,000–4,000 kcal a day) are genetic outliers. That is why they have social media careers. Those who cannot get lean without dropping the calorie counts absurdly low (below than predicted by calculators), find this unsustainable and drop out. There is enormous metabolic variance , just as there are peopel who are really strong or tall and can make a living at playing football or basketball.
Overall, the reason dieting fails so often is hiding in plain sight: the calorie deficit required to achieve and maintain weight loss is lower than assumed, which cannot realistically be scaled at a population level. Standard calorie calculators and advice “just eat less and move more, bro” overlook such variation or biological factors, The people who successfully maintain low body weights–and especially the people who build careers around fitness–are not necessarily representative of the population trying to imitate them or their clients.