Interactions of diet, exercise, metabolism, and weight change in humans

超加工食品的供应和消费增加与肥胖率上升有关，但过去的研究没有证明超加工食品是否会导致肥胖或不利的健康后果。我们最近完成了一项临床试验，调查人们在摄入由超加工食品组成的饮食时，是否比服用由未加工食品组成的(https://clinicaltrials.gov/ct2/show/NCT03407053).饮食时摄入更多卡路里尽管超加工饮食和未加工饮食每天提供的卡路里、糖、脂肪、纤维和大量营养素是匹配的，但我们发现，与未加工饮食相比，人们在接触超加工饮食时摄入了更多的卡路里。此外，人们在超加工饮食中体重增加，而在未加工饮食中体重减轻。因此，我们的研究结果表明，限制食用超加工食品可能是预防和治疗肥胖的有效策略。 关于肥胖及其治疗的相互竞争的理论对比了饮食脂肪和碳水化合物在促进过量卡路里摄入方面的相对作用。低脂肪饮食的支持者认为，由于高脂肪食物的高能量密度和低饱腹感指数，高脂肪饮食促进了被动的过度消费。低碳水化合物饮食的倡导者提出，碳水化合物含量高的饮食会导致胰岛素分泌增加，从而减少能量消耗，增加饥饿感。我们最近测试了非常低碳水化合物、生酮饮食的影响，发现对能量消耗没有显著影响，但没有评估食欲和自由卡路里摄入量。 因此，我们在20名成年男性和女性中启动了一项喂养研究(https://clinicaltrials.gov/ct2/show/NCT03878108)，以调查在一个4周的住院期内，随机交叉设计的两种测试饮食在两个2周期间摄入的自由能量摄入的差异。呈现给参与者的测试饮食将在卡路里和蛋白质方面进行匹配，但低碳水化合物饮食(占卡路里的10%)将是高脂肪(占卡路里的75%)，而低脂肪饮食将是高碳水化合物(占卡路里的75%)和低脂肪(占卡路里的10%)。

Increased availability and consumption of ultra-processed foods have been associated with rising obesity prevalence, but past studies have not demonstrated whether ultra-processed food causes obesity or adverse health outcomes. We recently completed a clinical trial to investigate whether people ate more calories when exposed to a diet composed of ultra-processed foods compared with a diet composed of unprocessed foods (https://clinicaltrials.gov/ct2/show/NCT03407053). Despite the ultra-processed and unprocessed diets being matched for daily presented calories, sugar, fat, fiber, and macronutrients, we found that people consumed more calories when exposed to the ultra-processed diet as compared to the unprocessed diet. Furthermore, people gained weight on the ultra-processed diet and lost weight on the unprocessed diet. Therefore, our study results suggest that limiting consumption of ultra-processed food may be an effective strategy for obesity prevention and treatment. Competing theories about obesity and its treatment contrast the relative roles of dietary fat versus carbohydrate on promotion of excessive calorie intake. Proponents of low-fat diets argue that diets high in fat promote passive overconsumption due to the high energy density and low satiety index of high-fat foods. Advocates of low-carbohydrate diets propose that diets high in carbohydrates lead to elevated insulin secretion resulting in decreased energy expenditure and increased hunger. We recently tested the effects of a very low carbohydrate, ketogenic diet and found no meaningful effects on energy expenditure, but appetite and ad libitum calorie intake was not assessed. Therefore, we have initiated a feeding study (https://clinicaltrials.gov/ct2/show/NCT03878108) in 20 adult men and women to investigate the differences in ad libitum energy intake resulting from consuming two test diets for a pair of 2-week periods in a randomized, crossover design during a single 4-week inpatient period. The test diets presented to participants will be matched for calories and protein, but the low-carbohydrate diet (10% of calories) will be high in fat (75% of calories) whereas the low-fat diet will be high in carbohydrates (75% of calories) and low in fat (10% of calories).