Debate has raged over whether excess calories or inadequate exercise is the main cause of the growing obesity epidemic. While we should all aim to meet the recommended minimum of burning 1,000 kcal per week in exercise, access to excess calories seems to be the predominent force behind the obesity epidemic, with 95% of Americans exceeding their maximum caloric allowance. We may be particularly prone to obesity due to our inability to break down uric acid, a compound formed from our metabolism of sugar and meat products that causes fat and salt retention.
In contrast to the many diet pills, which may not work, and caloric restriction, replacing animal products with plant foods may be an effective way to decrease calorie consumption. Not only do vegetarians naturally eat fewer calories, they also have higher resting metabolic rates, higher postprandial calorie burn and appear to lose weight more easily. Meat burgers may have 25% more calories than meat-free burgers and hot dogs may have five times more calories than veggie dogs. It appears that calories from plant sources are not processed in our bodies the same way as animal foods – the consumption of meat (poultry in particular) and milk was associated with additional weight gain. The opposite effect has been shown for plant products; participants in one study saw twice as much weight loss consuming the same number of calories when soy was consumed, and consuming nuts and dried fruit to does not appear to lead to the expected weight gain. This might be due to changes in our intestinal flora when we consume meat products, which may allow us to extract more calories from our food.
Industrial sugars are another source of empty calories and have also been linked to secondary health problems. Added sugars account for the majority of calories consumed each day by Americans, though consuming low calorie sweeteners may actually lead to greater weight gain by altering brain signals regulating satiation.
A better strategy for decreasing calories from sugar would be to decrease our consumption of sweet foods. Over time, our taste buds adjust to become more sensitive, making naturally sweet foods taste sweeter.
Excess calories, particularly from protein, may activate the TOR pathway in our cells, accelerating aging. The amino acid methionine may also play a role in this process. For children, increasing calories from plant food appears protective against the development of asthma. The fiber found in plant foods may be strongly protective against stroke. Ingesting more calories from plants also appears to lower IGF-1 levels, a strong promoter of cancer growth, more than simple calorie restriction. Cocoa has many antioxidants and is low calorie, but chocolate is one of the most calorie dense foods we can eat. Some plant foods even provide nutrition without containing hardly calories at all, such as vinegar or tea.
Topic summary contributed by Miranda.