There are a whole lot of ways to diet, and many an overweight person has tried them all. Low-fat, low-carb, high-fat, liquid, vegan, paleo, raw—the variations seem to be endless.
One common feature is the recommendation to avoid ultra-processed foods. You know what they are; inexpensive, convenient, ubiquitous, and with long shelf lives. They're high in sugars, calories, and fat. They also may not produce the same gut-to-brain signaling that less processed foods do, and that lack of signaling prevents feelings of satiety. These foods are designed to be overeaten. When manufacturers claim "bet you can't eat just one," they mean it.
While causality cannot be proven, the parallel trajectory is clear. The rise in obesity and complications such as type 2 diabetes have paralleled the increased consumption of ultra-processed foods worldwide.
A recent small randomized crossover studyadmitted 10 male and 10 female adults to an inpatient clinical research unit at the National Institutes of Health. The study sought to compare the effects of an unprocessed diet versus those of an ultra-processed diet in individuals in a strictly controlled environment. Each of the study participants was randomly assigned to one of the two diet approaches for the first 2 weeks, followed by an immediate switch to the other diet.
