More weight-loss research

In my previous post I considered some of the extrinsic, i.e. outside, factors that contributed to (or hindered) long term weight maintenance. A recent systematic review examines the intrinsic, i.e. internal, factors, that help people lose weight and keep it off. It confirms the findings of a 2005 review. Are you ready for the big secret?

Eat less and exercise.

I know, that is some crazy shit! Indulge me, if you will.

The 2005 study performed a systematic review — a carefully controlled, procedurized review of the available evidence, assessing both the quality of the evidence and what was found. So they didn’t just look at a bunch of studies; they excluded ones that sucked or didn’t measure up to the standards of rigorous peer review. The findings from the studies that passed the grading: Diet associated with exercise produced a 20% greater initial weight loss, and diet + exercise also resulted in a 20% greater sustained weight loss (of about 15 lbs) after 1 year than diet alone. But here’s one problem: In both groups, almost half of the initial weight loss was regained after 1 year. Thus, although diet + exercise is the best way to go, if people don’t fundamentally alter their habits and life patterns, the weight will come back.

The 2009 study did pretty much the same thing, and produced no surprises. Again, diet + exercise is better for sustained weight loss than diet alone, even for long-term studies (such as those lasting 2 years or more). But as the researchers note:

A combined diet-plus-exercise programme provided greater long-term weight loss than a diet-only programme. However, both diet-only and diet-plus-exercise programmes are associated with partial weight regain, and future studies should explore better strategies to limit weight regain and achieve greater long-term weight loss.

In other words, losing the weight is only half (or maybe even less than half) the battle. While diet + exercise is obviously the best method, it has to be a long-term commitment and you have to reconsider the habits and environment that helped you gain the weight in the first place.

Much has been made of the “diets don’t work” finding. People have interpreted it to mean that any attempts to change body composition are pointless — that somehow the body “knows what it wants” and has a magically determined setpoint. Well, that’s crap. What has a “set point” (which is almost entirely arbitrary) is your behaviour, habits, and cognitive approach. You might as well say your teeth have a “set point” of decay, or your armpits have a “set point” of funk. Sure, you have a set of biological cues that send you messages. But just like we don’t pee our pants any time we feel a sphincter tingle, we don’t need to eat a Twinkie whenever our brain decides the glucose thermostat is getting a little chilly.