April 12, 2017 | 3 minute read

There’s been some controversy about whether being overweight, but not obese, might actually link to a longer life. A few years ago a major study suggested that paradox. We wrote about it here.

For lower cancer risk, healthy weight is key. AICR’s reports find that overweight and obesity increase risk for 11 cancers, including colorectal and postmenopausal breast.

In this new analysis on weight and mortality, researchers used a person’s highest weight during the study and found that those who were overweight or obese had increased risk for early death. The data comes from 225,000 participants in the Nurses Health Studies (NHS I and II) and the Health Professionals Follow-Up Study (HPFS). It was published last week in the Annals of Internal Medicine.

Participants were followed for an average of 12 years. Compared to those who were normal weight, overweight participants (Body Mass Index or BMI 25-29.9) had a 6% increased risk of all-cause death; obese (BMI 30-34.9), a 24% higher risk, and for those with a BMI 35+, risk rose to 73%.

(At a height of 5′ 7″, overweight is 159-185 pounds, a BMI from 30-34.9 is 191-222 pounds.)

The participants reported their weight every two years, so researchers were able to determine an individual’s highest BMI during the study. This, the authors say, is a more accurate picture of how weight influences risk for early death compared to using weight at the beginning of a study, which is typical for many studies.

The authors also looked at how the highest BMI linked to specific causes of mortality. For heart attack (coronary heart disease), risk was especially increased: overweight 32%, obese 97%, and 35+ BMI was 334%. Cancer deaths also increased with higher BMI.

Sorting out how weight influences death can be tricky. In many studies, weight is reported at only one time, but that doesn’t capture all the variables: individuals may gain weight throughout life; weight loss often occurs several years before death due to illness; and smokers tend to have lower weight than non-smokers, but they also tend to die earlier from smoking related diseases.

That’s why this study’s more thorough look at individuals’ highest weight adds important information to our understanding of overweight and obesity risk.

In this study, the researchers point out that these participants are predominantly white and have high socioeconomic status. They are also health professionals. It is important to look at more diverse groups to determine if this applies to the general population.

For now, the best advice to help reduce cancer risk – and type 2 diabetes and heart disease –  is to work to avoid weight gain and lose weight if you are overweight. Start with small every day changes like walking a little longer, using a smaller plate and limiting foods with added fats and sugar. For more on reshaping your plate for a healthy weight read about our New American Plate way of eating.

This study was funded by the National Institutes of Health.