Health and Nutrition Research Landing Page
Body Mass Index (BMI)
The numerous findings showing that peanuts help you manage your weight all fall in line with the population studies showing that peanut and peanut butter eaters tend to have a lower Body Mass Index (BMI) (Sabate, 2007).
- The Adventist Health Study showed that those who ate more peanuts/nuts were less obese (Fraser, 1992).
- The Nurses’ Health Study showed that women who ate more peanuts/nuts were leaner (Hu, 1998).
- The Continuing Survey of Food Intakes by Individuals (USDA 1994-96) showed that children and adults who reported eating peanuts/nuts had lower BMIs.
When researchers at Purdue University conducted the first human study to explain this body of evidence, they fed peanuts by substituting them for other calories in the diet or by adding them to the diet (Alpher, 2002). What they found is that people naturally decreased what they ate at other times of the day when eating peanuts. This dietary compensation is thought to be one of the mechanisms contributing to why there is little or no change in body weight with peanut consumption.
The fact that eating peanuts reduces hunger may contribute to this occurrence. In addition to having protein and fiber that promote fullness, peanuts have a low glycemic index. This means that your blood sugar may not rise high and dip low, which can cause an increased appetite.
Another possibility the research points to is that all of the peanuts you eat might not be fully absorbed. That is, some of the peanut may pass through non-digested.
In combination with these other factors, research is showing that peanuts increase energy expenditure. One study that fed three ounces of peanuts daily for 19 weeks showed and 11% increase in resting energy expenditure (Alpher, 2002). This was confirmed in a second study and was also found to be true among obese individuals.
Although the research is emerging as to why peanut eaters tend to weight less and don’t gain, collectively, different mechanisms are probably contributing to this effect. The great thing is, we don’t have to wait to figure it out; we can still enjoy the benefits of eating peanuts, knowing that they are helping in managing our weight.