From Ergo Log
Overweight is unhealthy, but fat people who lose weight may actually become even more unhealthy. That’s the devilish dilemma facing millions of fat people. In 2005 Danish and Finnish epidemiologists showed that, in the worst-case scenario, fat people who lose weight almost double their mortality risk.
The researchers followed just under three thousand fat Finns – with a BMI of over 25 – born in 1958. In the 1970s some of the people in the group had attempted to lose weight. Some were successful and others weren’t. The researchers had data on the group up to the late 1990s.
By 1999 some of the Finns had died. The researchers discovered that two groups had a markedly higher risk of mortality: the fatties who had successfully lost weight in the 1970s and the fatties who had not tried to lose weight and had become even heavier. HR = chance of dying.
The figure immediately below shows the survival rate among the fat Finns that wanted to lose weight. The dieters who didn’t lose weigh weight were healthiest. In the lower figure you see the survival rate of the fat people who did not try to lose weight. In this group it was the fatties with a stable bodyweight who were healthiest too.
The fat people who lost weight by exercising more – probably Finns who started jogging – were in slightly better condition than Finns who only lost weight by dieting.
Healthy weight loss is not just about getting rid of kilos, but about achieving a body composition of little fat and lots of muscle. The fat Finns in the study probably became less healthy because they lost lean body mass.
PLoS Med. 2005 Jun;2(6):e171.