Exercise Won’t Make You Thin? Research and Reality
A 2009 Time Magazine article suggested exercise is not all it’s cracked up to be and that it won’t necessarily give you the svelte body you’d expect. However, the article was met with considerable backlash from key organizations such as the American College of Sports Medicine which issued an official statement categorically denouncing it on many points. In short, much of information was misrepresented or lifted out of context and did not properly frame important underpinnings surrounding exercise.
In this post from Christian Thoma, MSc, PhD candidate, he provides some of his wisdom and insights on the effects of exercise for weight control and offers a balanced and practical view on the matter. Take it away Christian!
I’ll put the take home message up front because it’s that important:
- Exercise is good for your health
- Any exercise is better than none
- If you can’t or won’t change your diet and/or you aren’t losing weight on the scales, it’s still worth exercising for health and just plain feeling better
There is a lot of confusion out there about the role of exercise in managing weight and body fat. You might be considering exercise or are already exercising in the hopes of shedding weight/burning the flab. Maybe it’s working for you, maybe it isn’t.
Ask researchers working in the area of obesity and weight control and they’ll tell you that most of the research shows that exercise alone does little to a person’s weight, and only modestly changes how much of that weight is fat and how much is everything else.
Being a scientist, I’ve looked at the studies and I’d have to at least partly agree. Many studies do show that, on average, the volunteers placed on exercise only programs didn’t change their weight very much, and even fat vs. muscle tended to change little.
Here come the buts, whys and the what you should know:
1) Many studies had people doing three weekly one hour moderate intensity exercise sessions. A week has 168 hours, so 3 hours represents a fairly small portion of that time. What you do with the 165 non-exercising hours is going to have a big effect. Unsurprisingly, the studies where people exercised more (i.e. they used more energy as a result of exercise) were more likely to show weight reduction. Some just had people exercise 5 or more times a week, others asked people to exercise for longer periods, or at higher intensities/more vigorously.
2) Study results are usually given as an average. No average change across a study’s participants still allows for a combination of:
- Some people reduce their weight/body fat
- Some people do not change; and
- Some people actually gain weight
Unfortunately, it doesn’t tell you what group you might fit into.
3) There are different ways people compensate for a new exercise program. Some are a little less active during the rest of the time, eat just a tad more at each meal, or both. It’s easy to overestimate the amount of energy exercise uses and underestimate what’s in our food. The classic example is the person going for a 30 minute walk and then rewarding their effort with a high energy snack. Also, remember the 160+ hours a week you’re probably not being very active in? These give you plenty of scope to be that little bit less active without even noticing.
4) Most of the effects of exercise on your health and how much energy you use are short-term, depending on the type of exercise and what’s being measured that can mean minutes, hours, or at most a few days after exercise. The effects of more vigorous exercise tend to last longer than those of less intense exercise.
5) Although a modest amount of exercise isn’t a panacea for weight reduction, it has a pretty good track record for helping prevent weight gain and improve pretty much every other aspect of health from blood pressure to stress.
So how can you use this information?
- You could combine exercise with making small changes to your diet like drinking fewer calories, e.g. drop the soda, juice, sugar in coffee/tea, and go easy on the alcohol. This way you’ll counter any tendency to eat more.
- You could follow Dr Bill’s advice to increase your non-exercise physical activity. This way you counter any tendency to do less outside of formal exercise.
- You could do more vigorous exercise or do exercise more frequently, e.g. high intensity interval training 3-4 times per week, or moderate exercise 5-7 days of the week. After all, both approaches have at least sometimes been found to reduce weight/body fat.
I agree with Dr Bill that the best exercise for you is that which you’ll actually do, but if you have no particular preference and your immediate goal is fat reduction, choose a programme that will get you fitter and stronger quickly, so that when you exercise you can really burn some energy. I’d back a combination of resistance exercise and high intensity interval training. It can be indoors, outdoors, use machines, barbells, dumbbells, kettlebells, elastic tubing, bodyweight, or anything else you have at hand. Both types of exercise are used successfully in those with chronic diseases all the way through to elite athletes.
Your muscles are the engines of exercise, so focus on activities and exercises that use as much of your body as possible to burn as much energy as possible, and keep your heart rate up. We as individuals are too varied to give specific recommendations, so seek out professional guidance, if not in person, then in terms of reputable websites or books. Also get the go ahead from a health professional, just make sure it’s one that actually has the sense to value exercise. And ease into activity by building up duration and frequency week to week.
Feel free to post questions in the comments. I won’t give out programs because I don’t believe this should be done without a proper face-to-face screening process being employed, but I’m happy to expand on this post.
Yours in Health,
Christian Thoma, MSc, PhD Candidate
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