Titchenal C A
Department of Nutrition, University of California, Davis.
Sports Med. 1988 Sep;6(3):135-45. doi: 10.2165/00007256-198806030-00002.
Understanding the effects of exercise on food intake is complicated by limitations of methodology. One primary limitation with human subjects is food intake assessment. Highly accurate techniques may not represent usual eating patterns. Present techniques representative of usual eating habits lack accuracy. Several independent variables also affect the results of exercise-food intake studies, even with laboratory rats where food intake measurements can be quite accurate. These variables include exercise protocols, subject characteristics, types and amounts of food available for consumption, environmental conditions, and sociocultural factors. Most investigations have focused on the effects of exercise training protocols on energy intake. When forced to run on treadmills, energy intake of laboratory rats usually decreases in males and increases in females. In response to forced swimming protocols, energy intake in male rats is usually unchanged and increased by female rats. In contrast, voluntary running (in running wheels) usually results in an increase in energy intake in both male and female rats. However, energy intake may also be unaffected or reduced in male rats given access to running wheels. These gender differences may be related to much lower levels of voluntary wheel running observed in male rats. The gender difference observed with rats is not apparent in humans. Energy intake of humans is usually increased or unchanged in response to exercise training programmes. However, when energy intake is increased, it is usually below the increased expenditure, resulting in negative energy balance. Highly trained athletes and lean individuals usually increase energy intake in response to increased physical activity, whereas, obese untrained subjects commonly do not change energy intake when exposed to exercise training. Few studies have investigated the effects of exercise on changes in food selection in laboratory animals; the results of studies with humans also have been inconsistent. Research results range from increased carbohydrate, fat, or protein consumption to no change in diet composition. Rats respond to detraining (cessation of exercise) with increased or unchanged energy intake. Men who detrain after 9 months of training regain bodyweight and body fat lost during training despite a reduction of energy intake and the percentage of calories from dietary fat. The relationship between exercise and food intake is complex. These often inconsistent or conflicting results reflect this complexity. Further understanding awaits additional research to clarify confounding variables.
方法学的局限性使得理解运动对食物摄入的影响变得复杂。人体研究的一个主要局限在于食物摄入评估。高度精确的技术可能无法代表通常的饮食模式。代表通常饮食习惯的现有技术缺乏准确性。即使在食物摄入量测量可以相当准确的实验大鼠中，几个独立变量也会影响运动与食物摄入研究的结果。这些变量包括运动方案、受试者特征、可供食用的食物类型和数量、环境条件以及社会文化因素。大多数研究都集中在运动训练方案对能量摄入的影响上。当被迫在跑步机上跑步时，实验大鼠的能量摄入通常在雄性中减少而在雌性中增加。对于被迫游泳的方案，雄性大鼠的能量摄入通常不变，而雌性大鼠则增加。相比之下，自愿跑步（在跑轮中）通常会导致雄性和雌性大鼠的能量摄入增加。然而，在有跑轮的情况下，雄性大鼠的能量摄入也可能不受影响或减少。这些性别差异可能与在雄性大鼠中观察到的低得多的自愿跑轮水平有关。在人类中未观察到与大鼠相同的性别差异。人类的能量摄入通常会因运动训练计划而增加或不变。然而，当能量摄入增加时，通常低于增加的消耗量，导致能量负平衡。训练有素的运动员和瘦人通常会因体力活动增加而增加能量摄入，而肥胖的未受过训练的受试者在接受运动训练时通常不会改变能量摄入。很少有研究调查运动对实验动物食物选择变化的影响；人体研究的结果也不一致。研究结果从碳水化合物、脂肪或蛋白质摄入量增加到饮食组成无变化不等。大鼠在停止训练后能量摄入增加或不变。经过9个月训练后停止训练的男性，尽管能量摄入减少且膳食脂肪热量百分比降低，但仍恢复了训练期间丢失的体重和体脂。运动与食物摄入之间的关系很复杂。这些往往不一致或相互矛盾的结果反映了这种复杂性。进一步的理解有待更多研究来澄清混杂变量。
