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Q: If you are overweight, what is more important: getting fit or losing weight?

A: You are alluding to what some people have called the fat but fit paradox. Let’s start with definitions of fitness and fatness.

Fitness, also referred to as cardiovascular fitness or cardiorespiratory fitness (CRF), is a measure of the performance of the heart, lungs and muscles of the body. Muscle performance includes measures of both strength and endurance.

Maximal oxygen consumption (VO2 max), a laboratory measure of the maximum amount of oxygen a person can use during exercise, is the optimal measure of CRF. However, self-reported physical activity is often used as a proxy for VO2 max in research studies because it’s much easier and less expensive to assess.

Fatness can be defined in many different ways. Body mass index (BMI), a calculation of your size that takes into account your height and weight, is used most commonly.

However, we know that measures such as body fat percentage, waist circumference, waist-to-hip, ratio and waist-to-height ratio tell us much more than BMI about a person’s health, metabolic risk and risk of death. Still, due to the ease and relative inexpensiveness of this measurement, BMI is used most commonly in research studies.

The fat but fit paradox suggests that individuals with obesity who are also active can experience a reduction in cardiovascular disease risk that supersedes the effect of their increased weight.

It’s no surprise that being more physically active is linked to lower levels of blood pressure, cholesterol and sugar compared to being inactive.

However, physical activity does not completely compensate for the negative effects of having either overweight status or obesity. In other words, individuals with overweight or obesity are at greater cardiovascular disease risk than their counterparts with normal weight, regardless of physical activity levels.

Thus, the existing evidence shows that physical activity reduces — but does not eliminate — the effects of overweight or obesity on cardiovascular disease risk.

So, if you are both overweight and inactive, what should you concentrate on first? The natural answer is both.

However, for my patients I have always advocated concentrating first on increasing daily physical activity and scheduling 10 to 15 minutes of moderate intensity exercise every day.

There are many non-weight related benefits of exercise, including improvements in energy metabolism, oxidative stress, inflammation, tissue repair and immunity. But don’t expect that you will immediately start to shed pounds with a bit more exercise.

Once your increased activity level becomes more routine, you are more likely to consider the ways you can reduce daily calorie consumption.

Also, you may wish to talk with your doctor about pharmacologic options to help with weight loss.

Q: I am in my 70s, and my health is good overall. But I wish I had more energy. Why do older people become less energetic? How can we boost our energy naturally?

A: As we get older, we lose energy-producing engines in the cells (mitochondria), and as a result, we make less adenosine triphosphate (ATP) — the molecule that delivers energy to cells throughout the body.

We also lose muscle mass, resulting in fewer cells, fewer mitochondria and lower ATP production. If you’re too tired to be active, it compounds the problem by further weakening and shrinking muscles.

Fortunately, a healthier lifestyle can help give you more energy. That means eating a diet low in added sugars and processed foods, with enough calories and nutrients to meet your needs; getting seven to nine hours of sleep each night; managing stress; and (if necessary) talking to your doctor about medication side effects.

And perhaps the fastest, most important way to boost your energy is to move more. The recommended amounts of exercise are at least 150 minutes of aerobic activity (such as brisk walking) per week, and at least two muscle-strengthening workouts per week. But studies have shown that any amount of exercise is beneficial.

For example, a review of almost 200 randomized controlled trials of resistance training, published online by the British Journal of Sports Medicine on July 6, 2023, found that people who did any strength training at all increased muscle mass and physical function compared with people who didn’t do strength training.

In addition to boosting your energy, it’s essential to use what you have wisely. Think in terms of “energy dollars” and be more frugal about the way you spend them. Strategies known as the “four P’s” can help.

Prioritizing. Think about what you need to accomplish in a day versus what you want to accomplish, and make the necessary activity your priority.

Planning. Planning how to use your energy will help you accomplish more. Planning could be scheduling just one major errand or appointment per day as opposed to three errands. Planning could also mean that you schedule rest breaks.

Pacing. Don’t try to rush through activities, which can use up all of your energy quickly. Rushing leads to fatigue and increases your risk of falling. Spread out your activity to give yourself time to recover between tasks.

Positioning. Maintain good posture when you’re sitting or standing. You’ll expand your lungs so they can take in more oxygen. And it might help to sit down during activities to reduce the amount of energy you’re using.

Howard LeWine, M.D., is an internist at Brigham and Women’s Hospital in Boston and assistant professor at Harvard Medical School. For additional consumer health information, visit health.harvard.edu.

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