Trying to devise an ideal diet by studying contemporary hunter-gatherers is difficult because of the great disparities that exist; for example, the animal-derived calorie percentage ranges from 25% for the Gwi people of southern Africa to 99% for the Alaskan Nunamiut. Descendants of populations with different diets have different genetic adaptations to those diets, such as the ability to digest sugars from starchy foods. Modern hunter-gatherers tend to exercise considerably more than modern office workers, protecting them from heart disease and diabetes, though highly processed modern foods also contribute to diabetes when those populations move into cities.
While no independent research has been conducted on the Whole30 diet specifically, diets like this one that eliminate entire food groups are bound to make you drop weight, experts say. That was the case for 96 percent of 1,600 Whole30 participants, according to a survey by the company. Most Whole30 dieters lost between 6 and 15 pounds, the survey found. But experts worry that restrictive diets with no room for error can set followers up for failure and prompt them to put the pounds back on – and then some – once the diet is over.
Research into the weight loss effects of the paleolithic diet has generally been of poor quality. One trial of obese postmenopausal women found improvements in weight and fat loss after six months, but the benefits had ceased by 24 months; side effects among participants included "weakness, diarrhea, and headaches". Any weight loss caused by the diet was merely the result of calorie restriction, rather than a special feature of the diet itself.
The WHO trial (so named because the international team of principal investigators contained World Health Organization members) tested the potential of clofibrate, a “pre-statin” cholesterol-lowering agent, to reduce heart attack morbidity and mortality. The investigators ultimately concluded that clofibrate "cannot be recommended as a lipid-lowering drug for community-wide primary prevention of ischaemic heart disease.” Nevertheless, clofibrate remained in use until 2002, when it was pulled for increasing cancer rates. In their review of studies such as the WHO trial, Uffe Ravnskov and David Diamond observe, “Despite the largely disappointing findings from 50 years of cholesterol lower[ing] trials, the indictment and conviction of cholesterol as the causal agent in CVD [cardiovascular disease] has stood the test of time. … [Yet] the grand effort to reduce cholesterol as a strategy to improve health has failed.”