It’s mid-January, and no doubt quite a lot of people will be persisting with New Year resolutions that have something to do with their health, with ‘losing weight’ being generally high on their list of priorities. Exercise is usually thrown into the mix here, and while walking my dog this morning I witnessed a distinct upturn in the number of joggers I normally see, despite the fact that there is quite a lot of snow and ice on the ground.
I am very much an advocate of exercise, and it certainly has a big part to play in fitness and health. However, I don’t rate it if weight loss (and even fat loss) is the ultimate aim. For more on this, see a previous post from August which attempts to explain why increasing exercise and activity is highly unlikely to lead to meaningful weight loss.
I was reminded of the relative inefficiency of exercise in terms of weight loss by a study published very recently in the journal Obesity [1]. It basically looked at the relationship between exercise and not weight loss, but weight regain (the regaining of weight after successful weight loss). The study assessed more than 4500 pre-menopausal women who had successfully lost weight (more than 5 per cent of their body weight over a two-year period), and then were followed-up over a 6-year period. Individuals who gained more than 30 per cent of the weight they had lost were defined as having been subject to ‘weight regain’.
The results of this study found that higher levels of physical activity were associated with less weight regain. For example, an increased in acitivity of 30 minutes per day was associated with reduced regain of 1.36 kg (3 lbs).
Risk of weight regain was reduced by about 30 per cent in women who maintained exercise at about 30 minutes or more per day.
More strenuous exercise was associated with more marked benefits. For example, jogging or running was associated with a reduced weight regain of 3.26 kg (7 lbs).
This study was epidemiological in nature, and therefore can only tell us about relationships between exercise and weight, and not that exercise definitely prevented weight regain. It might be, for instance, that those who exercise more also were more careful with their diets, and this accounted for some or all of the apparent benefit associated with exercise.
However, assuming for a moment that exercise did directly bring about the weight benefits seen, it occurs that there’s a lot of exercise going on here for relatively little benefit.
This study suggests that if, for example, you stepped up your exercise by 30 minutes per day over a six-year period, you could expect to be about 3 lbs lighter for it. That’s over 1000 hours of exercise to be not very much lighter at all.
The results are better for more strenuous activity, but a lot more effort would have to go into this too. Somehow, the thought of jogging or running for more than 1000 hours to be, at the end of it, 7 lbs lighter does not fill me with enthusiasm.
Let’s not draw too many conclusions from this study because, as I said, it is epidemiological in nature. However, its results do at least support the idea that, as strategies go, exercise is not particularly effective for the purposes of weight loss. Also, as the post I link to points out, intervention studies (studies which essentially compare the weight loss effects of exercising with non-exercising) have found the same thing. Taken as a whole, the logical conclusion is that exercise does not do much for weight loss.
This evidence does not, in my opinion, provide a good reason not to exercise. Activity and exercise likely enhance health and well-being in a variety of ways. However, I do think it’s important to be honest about what benefits are likely from any intervention. So, by all means take exercise, and preferably choose forms of this that are enjoyable and sustainable. And by all means lap up the psychological and physical benefits that can come as a result. Just don’t expect the exercise you take to help you lose much weight, that’s all.
References:
1. Mekary RA, et al. Physical Activity in Relation to Long-term Weight Maintenance After Intentional Weight Loss in Premenopausal Women Obesity 2010;18(1):167″174
