Common questions and misconceptions about diets: what does the scientific evidence really show?

The study of diet and nutrition is often filled with numerous myths and misconceptions. A Google Scholar search of “diets health” yields over 4 million results. This review examines frequently asked questions about diets and dietary habits. These questions include the following: 1) Is a caloric surplus necessary for building skeletal muscle? 2) Is it possible to lose body mass or fat mass without caloric restriction? 3) Is intermittent fasting better than chronic caloric restriction for weight loss? 4) Are there sex differences in the response to fasting? 5) Can diet alone fulfill the macro and micronutrient needs of exercise-trained individuals? 6) Is there an ideal dietary macronutrient ratio? 7) Are most of the benefits of diets in overweight/obese individuals due primarily to the weight loss itself? 8) Do DNA-based diets induce greater fat mass loss? 9) Does eating late at night result in a gain in fat mass? 10) Are there data (i.e. observational, randomized controlled trials, etc.) on the carnivore diet? 11) Is there a diet that is best for healthy aging and longevity? 12) Is there such a thing as “superfoods?” 13) Can one consume adequate protein on a vegan diet? 14) Do high-protein diets harm the kidneys? 15) Does a greater meal frequency lead to greater weight loss? 16) Are carbohydrates more “fattening” than dietary fats? To answer these questions, we conducted an evidence-based scientific evaluation of the literature on these topics regarding the diet category.