There has been a lot of controversy about the role of exercise in weight management. The old conventional wisdom has been that, to maintain weight, one needs to balance calories in with calories out, and that exercise is the way to boost the “out” side of the equation. That is still basically true, except we now know that it takes a lot of exercise to counterbalance a large intake of calories, and our bodies are real good at seeing that we eat more to fuel the extra exercise. Most research shows that the amount of exercise that improves our general physical and mental health (like 2 hours of moderate-intensity walking per week) is simply not sufficient to affect weight very much.
The fact that exercise had been oversold as a weight-loss aid has led to some very cynical articles claiming that exercise is practically useless for weight management (such as this and this). But these articles overlook two important facts:
1.) Thousands of reports of people who have lost significant amounts of weight and kept it off reveal that exercise is a key reason for their success. Many of these reports are featured on the National Weight Control Registry website (nwcr.ws), which tracks people who have been successful in losing weight and keeping it off. Here is how the co-author of the website summarizes the role of exercise:
The key [according to James Hill] is exercise. ‘Activity becomes the driver; food restriction doesn’t do it. The idea that for the rest of your life you’re going to be hungry all the time – that’s just silly.’ People in the registry get an average of an hour of physical activity every day, with some exercising for as much as 90 minutes a day. They also keep the fat in their diet relatively low, at about 25 percent of their calorie intake. Nearly all of them eat breakfast every day, and they weigh themselves regularly. ‘They tell us two things,’ Hill says. ‘The quality of life is higher – life is better than it was before.’ And ‘they get to the point with physical activity where they don’t say they love it, but they say “It’s part of my life.” … I think you pay the price for having been obese and you have to do a lot of activity to make up for that.’
2.) There is a very important form of activity that is technically not exercise, but is crucial in determining our ability to lose or maintain weight. It is “non-exercise activity thermogenesis” or NEAT, and it accounts for a very significant proportion of our energy output. An excerpt from Weight Management for Your Life summarizes this research:
Research at the Mayo Clinic by James Levine, MD, has clearly shown that the more we move throughout the day, the more weight we lose (or don’t gain). He calls this kind of movement NEAT, which stands for Non-Exercise Activity Thermogenesis. For most of us, NEAT accounts for far more of our daily calorie expenditure than formal exercise does (even fidgeting uses calories!). Levine found that thin people are on their feet an average of 2.5 more hours a day than their overweight counterparts. NEAT is responsible for between 20 percent (in very sedentary “couch potatoes”) and 50 percent of our total daily energy expenditure. Most of the rest of our energy expenditure is due to “basal metabolism” (calories used when we are at complete rest) which accounts for up to 60 percent; and “thermic effect of food” (digestion, absorption, storage) which accounts for 10 to 15 percent. Levine discovered that our individual NEAT level is largely biologically determined (possibly genetically) and that people with a naturally low level can be taught to increase their “non-exercise activity.” He recommends that we aim for 40 percent NEAT by changing the way we work, such as standing while working and walking around during meetings and while on the phone. He uses a treadmill going very slowly (1 mph) throughout the day (a “walking workstation”); this kind of easy activity doubles our metabolic rate and uses an extra 100 calories per hour (compared to sitting). This would be a great way to watch TV!
What is the take-home message from all this?
First, be wary of articles, even from prestigious sources, that take an extreme view. Life is never so simple, and weight management is especially complicated and multi-faceted.
Second, how active we are (whether through formal exercise or NEAT) has a major effect on our health and our weight: the less sedentary the better.
Finally, what and how much we eat is just as important as exercise and activity.
Please let me know what your experience with exercise and non-exercise activity has been.