Thursday, November 27, 2008

Is it smart to lose weight?

This seems a frivolous question with an obvious answer. But not so fast with your response. Let’s first clarify the question. If you find yourself losing weight without any planning by you, then your weight loss could be a sign of a medical condition. Off to your GP please. Then there are those that really don’t need to lose weight; a distorted view of a normal body shape has probably sent them into the world of eating disorders and weight loss. They too need some outside help.

Intentional weight loss
Let’s just say that your mirror has spoken in a frank manner: “Hey chunky! What’s with the extra curve?” You both then agree that a few kilos could be safely left behind and you join the masses that are “watching their weight”.

Every health authority urges you towards a healthy weight. It makes sense. An overweight person will likely experience a drop in blood cholesterol and blood pressure, while their insulin sensitivity improves. Perfect.

But there is another important question. Will this weight loss make you live longer? A Danish research group says: “Maybe, maybe not”.

Weight loss may not be healthy
At the Institute of Preventive Medicine, Copenhagen, five scientists checked out the research on weight loss and mortality and found that, out of nine studies, only two found a decreased mortality with intentional weight loss in healthy folk. Four found no difference in life span and, disturbingly, three studies found an increased risk of early death in healthy adults over a follow-up period of 13-22 years.

We have to be careful how we interpret these results. It may be that those who lost weight quickly are at a greater risk of early death because they tend to lose more muscle than those that lose weight gradually. There was a hint that mortality rate was higher in people under 60 years of age so they may have already had a pre-existing disease that was not obvious at the start of the study.

So, should you lose weight?
That is your choice. In some cases, it may be a necessity with extra body fat causing joint pain or uncontrolled diabetes. If you are less than 5kg (11lb) overweight, intentional weight loss may be more a cosmetic decision, rather than a health decision.

This review study raises many questions. For example,are those that have ‘dieted’ many times at greater risk than those that have intentionally lost weight 1-2 times? There are some pretty unhealthy ways to lose weight (purging, fad diets etc) that may have reduced life span too. Anyway, I think I’ll play it safe and make sure I don’t lose weight this Christmas.

Reference: Nutrition Reviews 2008; 66(7): 375-386

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