Some people envy others for their fine jewelry or luxury cars, I covet fast metabolisms. I am practically star-struck watching my friend’s lean 17-year-old son regularly plow through piles of food, totally carefree.
My personal calorie-burning engine is about average, so although I’d like to say I have higher-minded reasons, truthfully what gets me to the gym most days is the reward of being able to eat more. But working out takes time and effort. What if you could burn calories without breaking a sweat, simply by eating certain foods? It’s an irresistible idea that gets a lot of media attention.
About 81 million search results come up when you Google “metabolism boosting foods,” with slide shows, books, blog posts, articles, podcasts and more pointing out what to eat to burn more calories. Predictably, most claims, if not unfounded, are overhyped, over-extrapolated half-truths. I laughed out loud reading some of these pieces — one justified its recommendation to eat sunflower seeds to burn belly fat with a link to a study done on 144 broiler chickens. Seriously, broiler chickens. But, it turns out, some foods and drinks do have solid science behind them as likely metabolism boosters in humans. Even those with the most evidence won’t transform you into a calorie-burning machine — but they might make some difference and are worth considering.
One of the tricky things about making sense of these claims is that metabolism is very broadly defined. My Stedman’s Medical Dictionary says it is “the sum of the chemical changes occurring in tissue.” So, technically, anything that happens in your body is part of your metabolism. But I am zeroing in on a definition of metabolism most of us have in mind when we complain of ours being slow: the number of calories we’d burn in a day if we were just sitting on the sofa. That number is the sum of our basal metabolic rate, the calories the body burns carrying out basic functions such as breathing and repairing cells; and thermogenesis, the calories expended to digest and process food. There is evidence that certain foods and drinks can bump up that total. Physical activity is a third factor contributing to our overall daily calorie burn. It is the most variable factor, and the one we have the most control over.