Some low-carb advocates have claimed that most traditional hunter-gatherer societies consumed diets that were very low in carbohydrates.
I’ve even seem some suggestions that nutritional ketosis was “the norm” for these cultures. The majority of studies have shown that traditional hunter-gatherer (HG) societies typically consume between 30–40% of their total calories from carbohydrate, though the range can vary between 3–50% depending on the population studied and the latitude at which they live.
This assumption is a basic failure of logic, but it’s remarkable to see how often it happens.
A person has a life-changing experience with a VLC diet, so they assume that their friend will have a similar experience.
On the contrary, reviews of prospective studies looking at the relationship between fruit intake and diabetes have found that those with the highest intake of fruit had the lowest incidence of diabetes.
(8, 9)It is also worth pointing out that virtually all studies performed so far showing benefits of the Paleo diet in conditions like type 2 diabetes and obesity have used moderate carbohydrate (not low or very-low carb) versions of the Paleo diet.
After just two weeks on a ketogenic diet, this progression not only halted, it reversed: her memory returned, her mind was sharper, and she was far less confused and disoriented.
For reasons I don’t fully understand, some people identify so strongly with how many carbohydrates they eat that they take offense when a suggestion is made that low-carb diets may not be appropriate for everyone, in all circumstances.
Yet as impressive as very low-carb (VLC) and ketogenic diets can be in certain situations, that does not mean that these diets may not have some undesirable side effects over the long term—some of which we’re only beginning to understand.
For example, as I discussed with Jeff Leach from the American Gut project in a recent podcast, some preliminary research suggests that long-term ketogenic/VLC diets may cause adverse changes to the gut microbiota.
If you talk to practicing clinicians who work with patients on a daily basis, or spend any amount of time in internet forums or the comments sections of nutrition blogs, you’ll find numerous reports from people who either experienced no benefit from or were even harmed by following a low-carb diet.
What blows my mind is that the “low-carb zealots” seem completely incapable of accepting these reports at face value.