Healthy Weight and BMI Range for Older Adults

An obese man eats junk food.
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BMI (body mass index) is a key indicator of overall health. Guidelines recommend that all adults maintain a BMI between 18 and 25; BMI over 25 indicates overweight, while one over 30 indicates obesity. However, it is possible that a few extra pounds may not be as harmful to those over age 65 as they are for younger people, and that being underweight is more of a concern for older individuals.

How BMI Affects Older Adults

BMI is calculated by dividing your weight in kilograms by your height in meters squared. There are plenty of online calculators and charts that can help you determine your BMI based on standard measures (inches, pounds), if you prefer.

There are increased health risks associated with having a high BMI, such as heart disease, hypertension, diabetes, and vascular disease, and they apply across age groups. That said, there are relationships between BMI and health factors in older adults specifically that have led some experts—including the National Institutes of Health—to suggest that it may be beneficial for seniors to maintain a BMI between 25 and 27, instead of under 25.

One of the largest studies that set out to determine just how much BMI impacts the health of older adults was published in 2014 in the American Journal of Clinical Nutrition. Researchers collected BMI data from 32 studies, which included 197,940 adult participants (all older than age 65) who were followed for at least five years. They found that, for older individuals, being underweight increased the risk of death, but overweight did not.

In fact, several studies found that being underweight at age 65 was linked to poor health and shorter life expectancy. Being overweight or obese at 65 was only rarely linked to worse health outcomes or lower life expectancy, compared to those who were at a healthy weight at age 65. Interestingly, sometimes the overweight and obese study participants had better health outcomes, but this was not a strong enough trend to recommend that older adults deliberately become overweight or obese.

Health-related quality of life factors, such as social functioning, emotional health, and pain, are not worsened by a higher BMI in older adults, according to a Korean study that collected data based on interviews with 542 individuals with an average age of 74.

And additional research suggests that avoiding a low BMI is associated with more independence and that a moderately high BMI may not impair independence for older adults. In fact, a study published in the Archives of Gerontology and Geriatrics found that older adults with BMIs over 30 did not experience a decline in activities of daily living.

Weight Maintenance Goals

While this data is interesting, it is not an endorsement for ignoring excess pounds. Much more research is needed before the impact of weight on aging is truly understood. As mentioned, a number of chronic health conditions are made worse by being overweight, and science continues to be consistent about that. Because of this, there isn't a different weight range or BMI officially recommended for people older than 65 at this time.

The biggest concern for older adults is becoming underweight. Many medical problems, such as cancer, gastrointestinal disease, and neurological disease, can cause problems that prevent older adults from getting enough nutrition, resulting in a low BMI, often for the first time in their lives. It turns out that being underweight increases the risk of developing serious health problems and decreases your chances of recovery from illnesses. For example, underweight stroke survivors fare worse than their overweight or average weight counterparts. 

We don’t know from data what the ideal weight patterns are for longevity, but we do know from studying people who make it to 100 that being a healthy weight seems to be an important factor.

With respect to your own health, you should work with your doctor to set the right goal for you. Despite charts and calculators, target BMI is not the same for everyone and may need to factor in additional considerations. If you have diabetes, for example, weight loss may be recommended, while you may be advised to try to increase your nutritional intake if you have a condition such as anemia.

As you get older, health issues, changes in your level of activity, medications, and alterations in your metabolism can make it more challenging to adjust to your target BMI. You may need the help of a nutritionist, who can guide you with things such as caloric goals and whether you need to take vitamin and mineral supplements.

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