Exercise Will Keep You Alive, Professor Says, but Won’t Help You Lose Weight
Exercise is often touted as a key component of weight loss, but according to Herman Pontzer, a renowned expert on metabolism, this may not be the case. In his book “Burn: New Research Blows the Lid Off How We Really Burn Calories, Stay Healthy, and Lose Weight,” Pontzer challenges the notion that exercise alone can lead to significant weight loss.
Contrary to popular belief, Pontzer argues that while exercise may initially result in weight reduction, the body eventually compensates and returns to its original weight. This phenomenon occurs because the body has evolved to maintain a fixed daily energy expenditure, regardless of physical activity levels. The hypothalamus, a crucial component of the body’s metabolic system, works tirelessly to regulate energy expenditure within a narrow range.
This revelation has significant implications for weight-loss strategies. Pontzer asserts that if exercise does not directly impact weight, the primary factor contributing to weight gain must be the energy intake through food. In a lecture titled “Healthy as a Hunter-Gatherer – Insights From Small-Scale Societies,” organised by the UK’s New Scientist magazine, Pontzer states, “The only way to lose weight is to take control of what you eat.”
Pontzer’s research challenges the prevailing belief that reduced physical activity in modern life is a leading cause of obesity. His study of the Hadza, a physically active hunter-gatherer society in Tanzania, revealed that their energy expenditure is comparable to that of sedentary individuals in the US. Despite engaging in significantly more physical activity, the Hadza burn the same number of calories as their less active counterparts.
The key differentiating factor, Pontzer suggests, lies in Hadza’s diet. While their energy expenditure aligns with sedentary individuals, obesity is rare among the Hadza. This finding underscores the importance of dietary choices in weight management.
As an evolutionary biologist, Pontzer’s work delves into how our species’ past influences our present health and physiology. He investigates the impact of ecology, lifestyle, diet, and evolutionary history on metabolism and overall well-being. Pontzer’s primary concern is the obesity epidemic, and he seeks to understand how our bodies have adapted to the recent sedentary lifestyle and dietary changes.
The industrial revolution and the subsequent shift to a more sedentary lifestyle have presented a challenge for our bodies, which have not yet evolved to accommodate this change. Pontzer suggests that these recent changes may be responsible for the rise in modern ailments such as heart disease, obesity, and diabetes. In contrast, hunter-gatherer societies, like the Hadza, have a low prevalence of these conditions.
Pontzer attributes the obesity problem to the energy-dense and less filling nature of processed foods. He highlights that the radical shift in our diets, which occurred with industrialization, has injected excessive calories into our food. This overconsumption of processed food, he argues, is a significant contributor to weight gain.
