When weight loss is the goal, the number on the scale can take center stage. But for older adults, another question matters too: how can weight come off without sacrificing too much strength and physical ability?
A six-month clinical trial offers a useful, carefully bounded answer. Among adults aged 65 and older with obesity, a program pairing weight loss with both aerobic and resistance exercise improved physical function more than either type of exercise alone. Participants in all the exercise-and-diet groups lost weight, but those who did both forms of exercise had a smaller reduction in lean body mass than those assigned to aerobic exercise alone.
The study does not establish a one-size-fits-all plan, or show that exercise can prevent muscle loss entirely. It does highlight why weight management later in life is about more than pounds: maintaining the ability to walk, rise from a chair and handle everyday tasks is part of the health picture.
What the study tested
Published in The New England Journal of Medicine in 2017, the randomized trial enrolled 160 adults aged 65 or older with obesity. Researchers assigned participants to a control group or to programs that combined a weight-loss diet with aerobic exercise, resistance exercise, or both. The programs lasted six months, and exercise sessions were supervised.
Participants in the three diet-and-exercise groups lost about 9 percent of their body weight. The researchers also measured physical performance using a standardized score that included tasks related to balance, walking and getting up from a chair.
The combined aerobic-and-resistance group improved its physical-performance score by about 21 percent. The aerobic-only and resistance-only groups each improved by about 14 percent. These results suggest that, in this trial, combining the two kinds of training offered a larger functional benefit than either alone.
Weight loss was accompanied by some loss of lean body mass in every diet-and-exercise group. The decline was about 3 percent in the combined group and about 5 percent in the aerobic-only group; the resistance-only group lost about 2 percent. Lean body mass includes muscle and other non-fat tissue, so it is not identical to a direct measurement of muscle strength or quality.
Why the type of exercise matters
Aerobic activity challenges the heart and lungs and can support stamina. Resistance exercise—such as lifting weights or working against bands—asks muscles to produce force. During weight loss, the body can lose some lean tissue along with fat. The trial suggests resistance work may help limit that loss, while aerobic activity can contribute to conditioning and walking endurance.
The combined group’s greater improvement in physical function is also a reminder that health benefits may not be captured by weight alone. A person could see modest change on the scale while making progress in strength, balance or the ability to move through daily life.
Still, the study should not be stretched beyond its evidence. It involved a specific group of older adults with obesity, used a structured program and followed participants for six months. It did not prove that the same results will occur for every older adult, that the program prevents falls or disability over the long term, or that everyone should pursue weight loss.
Turning the finding into a safer conversation
For an older adult considering weight loss, the first step is not necessarily to start a demanding workout. Health conditions, medications, joint pain, balance concerns and nutrition all affect what is appropriate. A clinician can help assess whether weight loss is a suitable goal and whether a physical therapist or qualified exercise professional should help tailor activity.
Strength work can be adapted. Depending on a person’s abilities, it might begin with supported sit-to-stands, light resistance bands or other movements selected with professional guidance. The important principle is gradual progression, not copying a research protocol without supervision.
For adults generally, the U.S. Centers for Disease Control and Prevention recommends at least 150 minutes a week of moderate-intensity aerobic activity and muscle-strengthening activity on two or more days. Those are broad public-health targets, not a personalized prescription; people who have been inactive or have health limitations may need to build up gradually and seek advice first.
Food matters alongside exercise. A weight-loss approach for an older person should account for adequate nourishment, rather than treating a larger calorie deficit as automatically better. If strength, appetite, energy or day-to-day function worsens during weight loss, those are reasons to revisit the plan with a health professional.
A broader measure of progress
The trial’s clearest lesson is not that every person over 65 should lose weight or follow a particular exercise schedule. It is that when weight loss is pursued in older adults with obesity, preserving function deserves attention alongside reducing body weight. In this study, combining aerobic and resistance training was associated with the largest improvement in measured physical performance and less lean-mass loss than aerobic exercise alone.
That makes a useful goal more complete: not simply losing pounds, but supporting the strength and mobility that help people keep doing the things that matter to them.
