Healthy Weight and BMI Range for Older Adults

Being underweight is just harmful as obesity

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 Seniors

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.

Danger of Low Body Weight

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.

Contrary to popular belief, the evidence now suggests that, for adults over 65, being underweight increases the risk of death but being overweight does 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.

Health Risks and Challenges

While this data is interesting, it is not an endorsement for ignoring excess pounds. We know unquestionably that a number of chronic health conditions are made worse by being overweight, and science continues to be consistent about that. These include heart disease, high blood pressure, diabetes, gallbladder disease, osteoarthritis, gout, and breathing disorders such as sleep apnea to name just a few.

But of equal concern is the impact of low body weight on an aging body and the management of chronic illnesses.

To date, there are no official recommendations on what the ideal weight range or BMI should be for people over 65. What is advised is that every effort should be made to ensure older adults don't lose weight as a result of illness or poor nutrition.

And, that can be difficult given have chronic disorders are associated with impaired nutrition. Many conditions, 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.

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.

Weight Maintenance Goals

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.

What is just as important is to recognize when weight loss is occurring and taking steps to correct it before it become significant. Weight loss is not considered inevitable in seniors; it may suggest you are not achieving the ideal dietary goals for your age or a health concern that needs investigation. Early action is key.

Weight Gain Tips for Seniors and the Elderly

  • Incorporate foods with a high calorie-to-volume ratio into the diet, including nuts, nut butters, avocados, dried fruit, whole grains, pasta, chocolate, cheese, and full-fat dairy.
  • Eat five to six smaller meals per day rather than the traditional three.
  • Ensure a protein intake to 1 gram per kilogram per day.
  • Drizzle extra virgin olive oil over food which delivers 887 calories per 100 grams.
  • Prepare high-calorie meals, such as soups and casseroles, in bulk quantities so that they are always on hand.
  • Speak to your doctor about the appropriate nutritional supplements.
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