Whether losing weight helps improve health is one thing; whether people who lose weight can live longer is another. However, for decades, it was considered superfluous to delve into such a proposition. It wasn't until the early 1990s that scientists from the U.S. Health Department began to consider this question. They conducted a scientific investigation into whether overweight individuals could extend their lifespan by losing weight. To this end, they analyzed six related studies conducted between 1950 and 1990. The final evaluation conclusion was concise: "In conclusion, there is no basis from these six studies to prove that overweight individuals can extend their lifespan by losing weight."
Based on statistical probability, the researchers also examined the effects of both weight gain and weight regain due to the 'yo-yo effect' on lifespan. They thoroughly studied 13 long-term experiments, and the results were not only unexpected but even shocking: "Losing weight, even moderately or slightly, increases the risk of death!" Incredibly, the people estimated to have the longest lifespans were those who continuously and slowly gained weight during their adult years.
The idea that losing weight can extend life is based on a misleading assertion, namely that people of normal weight live longer, to some extent, than those with a large belly. But does this mean that a person who was overweight and then lost weight can have the same lifespan as someone who was naturally slender? A slender Greyhound, built for running, will certainly outrun a Pug in a race. But could a Pug, after losing weight to be as slender as a Greyhound, have a chance of winning? You see now, a 'skinny fat person' and a slim person are not the same concept, are they?
Surprisingly, the researchers found that, regardless of whether the subjects were above or below normal weight at the beginning of the experiment, the fewest deaths occurred among those whose weight increased slowly. This conclusion, of course, also applies to overweight people! Both rapid weight gain and loss are detrimental to health, and those whose weight fluctuates by about a kilogram have, according to statistical averages, poorer health than those who are slightly overweight.
We once again emphasize that this finding applies not only to overweight individuals but also to those of normal weight! Therefore, if you—purely from a physiological perspective—are always gaining a little weight throughout your life, you need not worry about it.