At what weight do people live longer?

Overweight and obesity are risk factors for a number of diseases and early mortality. We have discussed this in detail in our other articles (here, here). Based on this, one might assume that thin people live the longest.

But, as research shows, people who start adult life with a normal weight and later transition to being slightly overweight, but never obese, live the longest.

Adults in this weight category live longer than even those whose weight remains within the normal range throughout their lives. Normal weight is approximately equal to:

• Height minus 100 — for men
• Height minus 110 — for women

A more accurate measure is the Body Mass Index. To find out your Body Mass Index, you need to divide your weight (in kilograms) by your height (in meters) squared. For example, if your weight is 80 kg and your height is 1.8 meters, then the Body Mass Index will be 24.7.

Body Mass Index = Weight / Height²

Body Mass Index = 80 / (1.8 * 1.8) = 80 / 3.24 = 24.7

Norms for Body Mass Index:

• up to 18.5 — Low Body Mass Index
• 18.5–25 — Normal
• 25–30 — Overweight
• 30 and above — Obesity

Those who start adult life with obesity and continue to gain weight have the highest mortality rate.

The impact of weight gain on life expectancy is very complex. It depends on both age and the timing and magnitude of weight gain.

The main point is that those who start with a normal weight in early adulthood, gain a small amount of weight throughout their lives, and enter the overweight category in later adulthood, actually increase their expected lifespan.

Worrying trends have been identified for the younger generation, suffering from overweight and obesity, which is very likely to have an increased risk of mortality associated with further weight gain in later life.

1. In all generations, those who started with normal weight and moved to being overweight later in life, but never became obese, have the best chances of increased longevity.
2. Those who remain at a normal weight throughout life are in second place for longevity.
3. They are followed by those who are overweight, which subsequently remains stable.
4. Next are those with a low Body Mass Index who maintain it stably.
5. In the older generation, next in the list of longevity are those who were overweight but lost weight.
6. In the worst position are those who started with obesity and continue to gain weight.

Based on scientific data, it can be assumed that people who were slightly overweight at the age of 50 but keep their weight relatively stable are most likely to survive for the next 20 years.

In other words — slightly overweight adults without signs of obesity (with a Body Mass Index in the range of 25–30) have the best chances for longevity.