
Surprising new research has cast one of the irrefutable laws of weight loss into doubt.
[x_pullquote type=”left”]Calories in = calories out. Right?[/x_pullquote]
Everyone knows that to lose weight we must burn more calories than we eat. Exercise more, and you’ll burn more calories, so you’ll lose more weight.
Only, as a recent study by Pontzer has shown, this might not actually be the case.
In fact, according to their data, on the days when the study participants exercised MORE they didn’t burn any more energy than on their days of lower activity.
The Amazing Balance of the Body
The human body has an amazing ability to balance itself. For example, it’s constantly working to keep its core temperature within a degree or two. It carefully balances the blood for the right of amounts of minerals and acidity. There are many other examples where the body will regulate itself in this way.
Interestingly, the body may also be regulating how many calories you burn, regardless of how much you exercise.
Research Finds a Daily Calorie Plateau
When researchers strapped fitness trackers to study participants, they expected to see the calorie numbers add up in a certain way. Let’s take an example participant, Jim, whose body would burn 1500 calories in a day by doing nothing in bed. On any given day, if he does nothing but go to the gym, and burns 1000 additional calories there, you’d expect him to burn 2500 calories that day. The calories he burns should all add up… 1000 + 1500 = 2500.
This is not the result the researchers got. After a certain amount of activity, the number of calories burned hit a plateau. No matter how much more activity happened above this plateau, the body did not expend more energy over the course of the day.
Jim could have a plateau of 2300 calories. Despite doing activity that should equal 2500 calories for the day, his body would actually only burn 2300. He could have gone home from the gym 20 minutes earlier to watch tv, and still burned the same amount of calories.
This discovery revolutionizes the way we think about calorie expenditure.
The researchers offer a couple of explanations for the mysterious results:
- We all fidget throughout the day. It’s believed that when we exercise more, our bodies compensate by fidgeting less. When we’re worn out, we’re less active in all the little things our bodies do. It’s pretty difficult to track the micro-movements our bodies make as we fidget or balance, so you won’t see this reflected on your Fitbit. But fidgeting really adds up!
- Our systems slow down to conserve energy. For example, when females are very active their bodies produce less estrogen and reduce ovarian function. It’s as though the body is in panic mode. “We can’t make a baby if you’re going to be spending all your energy exercising! There’ll be nothing left to give to the baby!”
These are both evolutionary functions that would ensure our bodies can still function properly during hard times, when we may not be able to eat enough to make up for increased activity. While this concept seems foreign to many of us today, pregnant refugees fleeing Syria might depend on it for the health of their babies.
So, in these ways our bodies are working against our goals of burning more calories. But that doesn’t mean we should give up on physical activity! Cardiovascular exercise has numerous health benefits, including mental health. Keep doing that cardio, but be aware that adding more and more of it to your day won’t help you lose weight.
Is All Exercise Created Equal?
It’s also important to differentiate between cardiovascular exercise and strength training. When we lift weights and build muscle, that extra muscle takes energy to maintain. So, instead of burning 1500 calories just lying in bed all day, we’ll burn 1600. This has an ongoing effect, even on days when we get very little activity.
The difference between these two types of activity may provide some insight into the phenomenon I see in my practice as a dietitian. Men, more than women, tend to achieve more weight loss by hitting the gym. It’s very likely that women have less success losing weight at the gym because they tend to focus more on cardio than on weight training. When they put in that extra cardio, it’s not necessarily helping them reach their weight loss goals.
This research underscores, for both men and women, the problems with trying to accurately track calories on a day to day basis. Tracking your fitness with devices like Fitbits, and tracking all of your food with a smartphone app, has not been shown as a reliable weight management technique, particularly in the long term. These technologies don’t know when your body is going to slow down and burn calories slower than usual in order to conserve energy. They don’t know how much you fidget throughout the day. They don’t know when your reproductive system is going to be feeling extra reproductive.
Fitbits can’t beat the human body
In short, as amazing as today’s technology is, it’s no substitute for the incredible tech included in your body. Everybody is born with the innate ability to intuitively know how much to eat. It all starts with taking the time to check in with yourself before and while you’re eating to ask yourself the question “How hungry am I?” Your body will give you the answers once you slow down your eating and start listening to it.
When you tap into this knowledge, you feel like you’ve suddenly been gifted a super power. No matter where you go, no matter what food you’re surrounded by, you have the ability to eat exactly how much or how little you need. And most amazingly, what you need becomes what you want.
Sources:
- http://www.cell.com/current-biology/pdf/S0960-9822(15)01577-8.pdf
- http://link.springer.com/article/10.1007%2Fs11199-010-9800-8?LI=true#/page-1
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