It’s that time of year when dieting messages are loud, and everyone seems to know a secret to hacking our metabolism. But is altering our metabolism actually that easy? Today we’re busting common metabolism myths.
Let’s start with a definition. Metabolism is the process by which our bodies convert what we eat and drink into energy. As a result, most of the claims we hear about metabolism have to do with increasing our metabolism so that we can lose weight, but as we’ll learn these statements are not so simple.
Myth #1: Eating Breakfast Jumpstarts Your Metabolism
There’s no doubt that there are benefits to eating breakfast; it can provide vital nutrients and energy and satisfy hunger. But unfortunately, breakfast is not going to jumpstart your metabolism.
In fact, this study, though small, found no difference in calories burned over 24 hours between people who ate or skipped breakfast. While some think skipping breakfast will lead to less calories eaten throughout the day, the same study noted that those who skipped breakfast compensated by having a larger meal for lunch and dinner. Additionally, this randomized controlled trial found that eating or not eating breakfast had no discernable effect on weight loss in those who were attempting to lose weight.
Myth #2: Eating Smaller, More Frequent Meals throughout the Day Increases Your Metabolic Rate
The idea is simple: whenever we eat food, our body must burn calories to break the food down and absorb the nutrients. So, if we were constantly eating, then couldn’t our bodies constantly be burning calories?
Not quite. The thermic effect of food (TEF) is the energy we expend to process, use, and store the nutrients in our meals. However, the temporary boost in our metabolic rates is directly proportional to how much and what types of foods we eat. So, while eating six small meals over the course of a day would slightly increase your metabolism six times, eating three larger meals per day can result in a similar overall effect through three proportionally larger boosts.
Notably, one of the subcommittees for the 2020 Dietary Guidelines Advisory Committee – who create the scientific report that the Dietary Guidelines for Americans is based on, focused on frequency of eating. Their finding? There isn’t enough evidence to determine the relationship between the frequency of eating and growth, size, body composition and risk of overweight or obesity.
Myth #3: Certain Foods Can Fire Up Your Metabolism
You’ve probably seen claims about the idea that certain superfoods or supplements have the ability to fire up your metabolism. The surprising truth? There is some validity to these claims, but they are often overhyped. In sum, even in foods where there is an effect on metabolism, it is small and research is typically not conclusive.
Let’s review a few commonly touted metabolism-boosters – catechin, found in green tea, capsaicin, found in hot peppers and ginger.
This meta-analysis did find a significant positive effect on energy expenditure after consuming catechin-caffeine mixtures and caffeine-only supplementation. It is estimated that average energy expenditure increased by 4.7% and 4.8% from catechin-caffeine mixtures and caffeine-only supplementation, respectively. However, one moderator of these results was BMI; those with a higher BMI at baseline corresponded to higher energy expenditure.
Moreover, while more research is needed, one randomized controlled trial among overweight women found that taking green tea, capsaicin and ginger supplements each day for eight weeks had beneficial effects on weight, BMI, markers of insulin metabolism and plasma GSH levels.
While some research suggests certain compounds such as those found in green tea or hot peppers may have a temporary effect on our metabolism, the less exciting truth is that those impacts are small and a balanced diet that can include these foods remains our best bet for improved health, long-term.
Myth #4: Eating Late at Night Slows Your Metabolism
As far as metabolism myths go, this one seems reasonable. We lie in bed while we sleep, so it stands to reason that we don’t burn many calories during that time. If we eat right before sleeping, wouldn’t that lead to storing that food as fat because it’s not being used to power our daily activities?
There are two issues with this premise; first, our metabolisms do not slow down to a crawl, even when we are sleeping. Our bodies are still active at night, keeping us functional and healthy through processes like breathing and maintaining our heartbeat. This study shows that metabolism actually increases during sleep in leaner individuals, while slowing down in people with obesity.
Secondly, our bodies are in a constant state of flux when it comes to using or storing energy. Our bodies are constantly switching between anabolism – building, and catabolism – breaking down. They’re pulling energy from stores when needed and refilling the stores constantly. In short, having a late dinner or snack at night won’t automatically lead to a slowed metabolism or weight gain.
The Bottom Line
In summary, our metabolism functions consistently on a day-to-day basis as our bodies are constantly breaking down and storing nutrients. Though the time of day that you eat has little effect on your body’s overall metabolism – and certain foods are not going to lead to a momentous boost of your metabolism, what does matter is that you make dietary and physical activity choices that align with your unique preferences and health needs.
For tips on how to make healthful changes to your diet, check out these resources:
- Four Tips for Eating Healthy Without Going on a Diet
- Small Nutrition Shifts for the New Year
- The Benefits of Mindful Eating: Video
This article includes contributions by David Hu, Kris Sollid, RD and Alyssa Pike, RD.