From Garry Taubes, The Curious Lessons of Calorie Restriction, in which he contrasts his ad libitum low-carb approach to Peter Attia. He writes:
Where Peter and I diverge in our thinking in this case is on a simple but critical point: when carbohydrate-restricted diets are prescribed for weight loss—i.e., a version of DR, by Peter’s thinking—and particularly high-fat, ketogenic diets, which are absent all carb-rich foods, they are prescribed ad libitum. Eat as much as you want, just abstain from the carbohydrates. Clinical trials (e.g, here) suggest they work at least as well as calorie-restricted diets, but they do so without prescribing calorie restriction.
Garry Taubes built a career as a public intellectual promoting low-carb dieting. Similar to Jason Fung, he’s yet another guy full of theories who has written many books and articles, but whose methods do not actually work when put to the ultimate test: reality. Theories are useless if people in the real world are unable to apply them.
As for the aforecited clinal trial, “A Low-Carbohydrate as Compared with a Low-Fat Diet in Severe Obesity“, the results are much more modest or even spurious. The study says, “An analysis including all subjects, with the last observation carried forward for those who dropped out, showed that subjects on the low-carbohydrate diet lost more weight than those on the low-fat diet (mean [±SD], –5.8±8.6 kg vs. –1.9±4.2 kg; P=0.002)”.
This sounds good, except the participants were morbidly obese, with BMIs in the 40-45 range and on average weighing 130 kg, which is a lot. The apparent success of the low-carb group can easily be explained by glycogen depletion, especially for participants who are so obese and hence carrying considerable glycogen in their stores. This quicky levels out once the glycogen is depleted.
Moreover, it’s easy to find studies that show no difference in weight‑loss success between low‑ and high‑carb diets, so this looks like cherry‑picking on his part. Also, the study was from 2003 and appears not to have been replicated. Finally, a 6 kg weight loss is only about a 4.5% drop from a starting weight of 130 kg and is hardly indicative of long‑term success when so much weight remains to be lost. It’s a good start, but for a diet to count as a success it needs to work long term.
This is not to single him out. This is true of most of these ‘health influencers’ and self-anointed experts. It’s a lot of cherry picking and theories that does not hold up.
On Reddit, there is no evidence participants on low-carb communities (e.g r/keto, r/carnivore, r/Adkins, r/animal-based, r/zero-carb etc.) are any more successful at dieting compared to plant-based participants. The common denominator is they all struggle to lose weight. (At least plant-based dieting is much cheaper and better for the environment, so it has that going for it.)
Eating ‘high-fat, ketogenic diets ad libitum’ as Taubes prescribes seems like a recipe for weight gain due to high calorie density. Indeed, as shown below on Reddit, weight gain on carnivore is quite common:
This makes sense. Animal products tend to be extremely calorie dense. Paleolithic humans have always sought and prioritized meat and fat when it was available, as those provided much higher energy density compared to plants. But animal meat was so scarce that it was impossible to become obese from eating too much of it. Even the advent of farming did not change this. It was not until the early 20th century did meat and dairy production become cheap enough at scale to replace carbs as a primary food source.
In fairness, similar anecdotes can easily be found on Reddit of people gaining weight on plant-based diets, mainly due to overeating oils, hummus, nuts, avocados, granola, and nut butters—all of which are also very calorie-dense due to their high fat content.
What this shows is that dieting is highly individualized. What works for some people will not work for everyone. But the evidence that low-carb is superior is extremely lacking. Low-carb dieting has gained popularity in recent years, yet obesity rates keep rising. If there were a ‘perfect diet’ it would be common knowledge by now. It would not be endlessly debated. Everyone would just do ‘the diet’ and have the results to show for it.
These health influencers also tend to blame obesity on insulin resistance. Or insulin spikes due to carbs. But all food causes an insulin spike, except maybe vegetables due to high water content. That is how digestion works. Otherwise you’d have type 1 diabetes. Moreover, if eliminating carbs under this assumption of not spiking insulin was correct, keto/carnivore diets would be overwhelmingly successful; clearly they are not as shown above.
I think people confuse or conflate the pleasurable dopamine rush from eating with an attendant insulin spike. But this has nothing to do with the macro composition of the food, but rather its density and palatability (so-called hyper-palatable foods). This is why eating a buttered steak or lobster feels as good as cake or ice cream despite the former having no carbs. It’s more to with rich flavor and high calorie density than certain foods spiking insulin or not. This can explain, similar to social media addiction, how overeating may similarly be caused by an overstimulated reward system in the brain.
As for insulin resistance leading to obesity, this possibly gets the causality wrong. There is compelling evidence insulin sensitivity leads to obesity, which later transitions to insulin resistance, possibly due to inflammation. Insulin is used to transport glucose to cells, which is stored as glycogen and any surplus converted to fat. This process being impaired means there is too much glucose in the blood, which is peed out and manifests as type 2 diabetes. This hinders weight gain to some extent.
But under insulin sensitivity or hyperinsulinemia, the body is too effective at using insulin or there is too much insulin in the blood, leading to fat storage and low blood sugar, which promotes more eating to raise the blood sugar, and more weight gain. Conversely, exogenous insulin leads to weight gain due to the body absorbing more glucose, which can be converted to fat, which is why people with both types of diabetes gain fat weight from insulin therapy.
I am not saying with 100% certainty this is correct or the reason for obesity, but just blaming insulin resistance or ‘carbs spiking insulin’ does not hold up well either. Better explanations are needed.