Exercise only marginally affects weight loss, according to Julia Belluz of Vox. In her video, she explains that our resting metabolism burns the vast majority of calories. She states that exercise only affects around 30% of calories burned during a day. Citing a 2012 study, Belluz suggests that the body compensates for calories burned during physical activity by conserving them elsewhere. The real issues for Americans are overeating and eating unhealthy food, she implies. The idea that physical exercise can compensate for a calorie-filled diet is wrong, infers Belluz.
Compared to changing one's diet, exercise results in more fat being burned, argues K. Aleisha Fetters of US News. She looks at research, which suggests that trying to lose weight by changing eating habits makes the body activate a starving mechanism, which dramatically slows down its metabolism, resulting in less fat being burned. In contrast, exercise grows muscle, which make the body’s metabolism burn more calories when not working out, claims Fetters. She speculates that metabolism is decisive for weight loss and exercise is the only way to improve it.