Exercise is a key component of any weight-loss plan, but it’s especially important for people who’ve inherited a tendency to easily put on pounds. Results of a study published in the August issue of PLOS Genetics adds some granularity to that maxim, parsing 18 activities by their effect on the inherited risk of obesity.
Six activities come out on top, with the winner what the researchers call “regular jogging.” The opening image is of my husband Larry (at the rear) and three of his friends (Lou Peluso, John Lobos, and Rob Colborn) from many moons ago, doing what I would call running, which oddly was not one of the 18 forms of exercise in the study. I’ll assume that if “regular jogging” minimizes obesity risk the best, running should at least equal that effect.
The standard measure used to classify us as underweight, okay, overweight, or obese is body mass index (BMI), which is weight taking into account height (specifically, weight in kilograms divided by the square of height in meters). Here’s a BMI calculator; the World Health Organization considers obesity to start at a BMI of 30.
- body fat percentage
- waist circumference
- hip circumference
- waist-to-hip ratio
Adding these four also has health implications. Hip circumference predicts elevated risk of diabetes, for example, and waist circumference and waist-to-hip ratio reflect abdominal girth (“central obesity” aka “belly fat”), which is associated with higher risk of heart disease.
Past studies haven’t pinpointed which types of exercise are most effective at combatting obesity because they considered only BMI and/or didn’t distinguish types of exercise. Wan-Yu Lin of National Taiwan University and colleagues sort that all out in their new paper, surveying 18,424 unrelated Han Chinese adults aged 30–70 years who participated in the Taiwan Biobank, a “big data” biomedical research database. Participants were asked to list up to 3 types of regular activities; about 41% reported being regular exercisers.
The researchers evaluated the degree to which genetics contributes to each of the five measures of obesity using a metric called a polygenic risk score, which reflects the input of many genes contributing with varying degrees to a trait or illness. How the polygenic risk scores changed when calculated for people who did one of the 18 types of exercise revealed the effect of the activity on the inherited tendency to become obese.
Waist-to-hip ratio was the only one of the five obesity measures that didn’t respond to exercise. Overall, six types of exercise appeared to counter the genetic effects on at least one obesity measure.
Regular jogging blunted the genetic effects on obesity the most for three measures: BMI, body fat percentage, and hip circumference.
Coming in next were mountain climbing, walking, exercise (aka power) walking, international standard (aka ballroom) dancing, and an extended practice of yoga (type unspecified).
The researchers offer possible explanations for the findings of what does and doesn’t affect genetic risk of obesity:
- Cycling, stretching, and qigong require less energy expenditure than the 6 winning exercises.
- Swimming, especially in cold water, stimulates appetite and food intake.
- Dancing to music videos displayed on a screen doesn’t measure up to the exertion required for ballroom dancing.
Not enough people reported doing weight training, badminton, table tennis, basketball, or tennis to meaningfully evaluate those activities, the researchers add, but table tennis and Tai Chi were associated with diminished abdominal girth, probably due to turning the waist repeatedly.
Perhaps the more important take-home message is that “The benefits of regular physical exercise are more impactful in subjects who are more predisposed to obesity. These results indicated that although hereditary factors are critical to obesity, performing different kinds of exercise can modify this relationship to various extents,” the researchers conclude.
A similar studying using information from the UK Biobank pinpointed fast walking as the factor most likely to counter inherited obesity tendency, and that’s similar to jogging. So the results of the Chinese study are probably applicable to other populations.
The findings are good news! Genetics isn’t destiny when it comes to tendency to carry too much weight. By going beyond BMI and assessing 18 forms of exercise in a large group, the study adds to what we know about the beneficial effects of certain exercises.