Physical activity helps control your appetite
Being sedentary promotes more eating
The famed Tufts University nutritionist Jean Mayer established the relationship between caloric intake, body weight, and physical work in a group of 213 mill workers in West Bengal, India. These workers engaged in a wide range of physical activity, from sedentary to very hard work. The sedentary workers ate nearly as much food as workers with heavy physical work. Sedentary workers were heavier than those with heavy physical work. Mayer found that caloric intake increased with activity only within a certain zone (“normal activity”). Below that range (“sedentary zone”) a decrease in activity was not followed by a decrease in food intake—but by an increase. Body weight also increased in the sedentary zone. Mayer proposed that food intake became dysregulated at low levels of physical activity.
A 2015 study of 421 US adults with an average age of 27 years who were followed over one year came to the same conclusion. Physical activity was measured objectively with arm-mounted instruments. Participants were classified in five groups of increasing physical activity. Those in the bottom group had 11 times fewer daily minutes of moderate to strenuous physical activity than the top group. Participants in the inactive group also had significantly greater fat mass, less energy expenditure, and fewer steps per day than participants in the most active group. As body weight increased, physical activity declined. Calculated energy intake increased as physical activity increased, except for participants in the lowest activity group. Participants in the two lowest physical activity groups showed significantly higher cravings for savory foods (French fries, burgers, pizza) compared to participants in the highest activity group. The threshold at which optimum energy balance occurred and above which appropriate appetite regulation occurred corresponded to about 7,100 steps per day. Moderate amounts of physical activity may play an important role in body weight management by regulating appetite. Setting a daily goal of getting at least 7,100 steps could help you maintain a healthy body weight and avoid chronic diseases.
A recent narrative review of studies investigated effects of sex, fat mass, and habitual physical activity on energy intake and appetite-related hormones. Results showed that sex and fat mass did not affect appetite or energy intake in response to short- or long-term exercise interventions. People with higher levels of habitual physical activity may better adjust energy intake due to increased sensitivity of the appetite control system.
Studies suggest that high energy expenditure and high energy intake predict lower weigh gain. A recent study provided confirming evidence using data from 16 healthy adults who were confined individually to a 10 feet x 10 foot metabolic chamber for three days (sounds like fun!) while consuming one of four diets and performing either low, medium, or high amounts of physical activity on a treadmill. The metabolic chamber allowed researchers to measure energy intake and expenditure precisely. Researchers measured concentrations of the appetite hormones ghrelin (higher levels mean greater hunger) and GLP-1 (lower levels promotes stomach emptying and increase food intake). Regardless of the level of energy balance (excess caloric intake, or insufficient caloric intake, or caloric intake matched with energy expenditure), low energy turnover (low physical activity) led to increased ghrelin, reduced GLP-1, and increased feelings of hunger. Thus, better appetite control occurred at high levels of physical activity due to better control of hormones that affect appetite and not as a direct consequence of burning more calories.
Long-term physical activity appears to improve appetite control in younger adults. Yet, the effects in older adults remain poorly understood. Researchers conducted a systematic review and meta-analysis of 13 studies of blood glucose and the hormone leptin in adults over age 60 years in response to various types and intensities of physical activity. Five of the studies showed that physical activity interventions significantly reduced fasting glucose and leptin compared to non-activity controls. Decreases in glucose and leptin suggest that physical activity increases the body’s feeling of satiety, thereby reducing appetite.
Getting plenty of physical exercise will help you control your appetite, maintain a healthy body weight, and avoid chronic diseases.