Tuesday, September 7, 2010

Is weight loss good for overweight people ?

Sensible answer: of course it is. I mean, haven’t you seen all those public weight loss campaigns? When overweight folk lose weight, their health risks tend towards normal, that is, blood pressure drops, blood glucose lowers and blood cholesterol improves. A good thing, no? Not so fast, say a couple of American scientists who have crunched the numbers.

Intentional vs unintentional

Previous research has revealed that weight loss is linked to an increased chance of dying. Yes, that’s right, weight loss = early death. Clever readers will note that sick people usually unintentionally lose weight before they die, so such people will skew the statistics. There are other confounding factors too. Intentional weight loss is often via an unbalanced and low nutrient starvation diet (do you feel just too vibrant and joyful? Then try the Israeli Army diet) and semi-starvation has never been associated with longevity. These diets often mean a loss of muscle tissue and not just body fat. So, we have to be careful when we say that weight loss increases the chance of early death.

Too much weight loss unhealthy

Anyway, the statisticians looked at over 6000 men and women who were 50 years plus. They were followed for about 20 years and in that time 1600 died. Once they had adjusted for age, health and smoking and all the other things they adjust, guess what? If you lose more than 15% of your weight, whether you are male or female, obese or overweight, you die earlier than if you had lost only 5% of your weight. Women doubled their risk of early death and men increased their risk one and a half times by losing over 15% of their weight.

Let’s say you weigh 120 kg (265 lb) and lost 18 kg (40 lb) then you have probably brought your funeral forward. Are you listening at The Biggest Loser as you cheer Bob or Jane who has gone from 140 kg to 85 kg in a 12 week season?

What does it all mean?

Not every chunky person needs to lose weight. It is well regarded that people over 75 years do better and live longer with a little extra padding. The overweight unwell shouldn’t be placed on weight loss programs either. An otherwise healthy overweight person should lose weight slowly and not use televised “reality” weight loss programs as a guide.

This study is not saying that overweight people won’t benefit from weight loss, but it is making us ask whether encouraging a huge weight loss down to a supposed “ideal weight” is a good idea for everyone. Being very overweight is not healthy; promoting big weight loss doesn’t appear to be wise either. Right now we just don’t know what is a healthy rate or level of weight loss. The current advice for the overweight to lose around 0.5 kg (1.1 lb) a week and accept they probably won’t ever be super-lean is still the best advice.

Reference: International Journal of Obesity. 2010; 34: 1044-1050


Rob McAllister said...

Glenn is it good to lose say 10% at one stage then say a year later lose another 10% etc to get down to a "good" weight overall. Does this having a good gap in the program work well for you or is it a problem like you spoke about in your article.
Thanks Rob

Glenn Cardwell said...

Thanks Rob. The research wasn't able to determine what was an ideal weight loss. And remember, this was in people over 50 years so the situation may be different in young folk, who are likely to be more resilient to changes in body weight. As most people gain weight gradually, often 2-5kg every decade, it makes sense to lose gradually too, like say 5kg per year. Of course, people want any extra fat to be lost quickly and I suspect that is part of the problem - rapid weight loss can't be healthy. It is all more evidence that it is always best to never gain too much extra fat in the first place.