A new study led by researchers at Kanagawa University of Human Services in Japan has found that a short-term program combining a low-carbohydrate diet with resistance training can lead to meaningful weight loss, regardless of a person’s genetic risk for obesity.
This discovery offers hope for individuals who may feel discouraged by their genetic background.
Obesity remains a major global health problem, with over 640 million people affected. It raises the risk for many serious diseases, including type 2 diabetes, heart disease, certain cancers, and early death.
While lifestyle changes such as better diet and increased physical activity are standard tools for weight management, results often vary between individuals—even when programs are carefully structured.
Researchers wanted to find out why. Some of that variation may be due to environmental or social factors, like access to healthy food, exercise options, medications, or even sleep. But there is also growing interest in the role of genetics in how people respond to lifestyle changes.
In this study, researchers compared two ways to predict weight loss success: a genetic risk score based on 75 specific genetic variants (SNPs) and an “efficiency score” that reflects how well an individual responds to diet and exercise.
The study involved 145 participants, mostly women, between the ages of 20 and 69. They completed an 8–12-week program that included a low-carb diet and supervised resistance training.
The diet restricted carbohydrate intake to around 50 grams per day and encouraged protein intake of 1–2 grams per kilogram of body weight. There were no restrictions on fat.
Participants also completed 16 training sessions, one or two times per week. Exercises included squats, bench presses, crunches, and other strength-training moves, with trainers adjusting the difficulty based on participant progress.
By the end of the program, participants experienced clear improvements. Average BMI dropped from 27.6 to 23.8. Average weight fell from 71.6 kg to 61.9 kg, and body fat percentage decreased from 36.1% to 28.4%. Blood pressure also improved.
However, researchers noticed that not everyone lost the same amount of weight, and they looked for patterns to explain the differences.
They found that the genetic risk score had only a small connection to how much weight or fat people lost. While people with higher genetic scores tended to start with higher body weight, these scores did not predict who would lose more weight during the program.
In contrast, the efficiency score—a measure based on how well participants responded to the intervention—was much more useful in predicting results.
The efficiency score showed a strong link to how much participants reduced their BMI and body fat. For example, in models adjusted for age, sex, and how often participants attended training, the efficiency score explained over 34% of the variation in BMI changes.
Meanwhile, the genetic score explained very little. When results were broken down by sex, the efficiency score predicted weight loss in both men and women and predicted fat loss in men more clearly than in women.
In conclusion, this study suggests that a person’s ability to lose weight through diet and exercise in the short term may not be limited by their genetics.
While genetic factors may influence starting weight, they don’t appear to determine how much progress someone can make in a structured program. Instead, personalized efficiency scores may be a better way to predict outcomes and guide treatment.
These findings offer encouragement to anyone working to manage their weight: short-term success is possible with the right program, regardless of your DNA.
If you care about weight loss, please read studies that hop extract could reduce belly fat in overweight people, and early time-restricted eating could help lose weight.
For more health information, please see recent studies that Mediterranean diet can reduce belly fat much better, and Keto diet could help control body weight and blood sugar in diabetes.
The study is published in Obesity.
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