Physical activity helps teenagers with obesity lose weight and reduce body fat, according to a 2026 Cochrane systematic review of 30 studies involving 1,508 teens. Gram Research analysis found that adolescents who exercised lost approximately 1.9 kilograms more than those who didn’t exercise, and their waist circumference decreased by about 2.9 centimeters. However, researchers rated the evidence quality as low to very low, meaning better studies are needed to confirm these findings and determine which types of exercise work best.
A major review of 30 studies involving 1,508 teenagers found that physical activity can help young people with obesity lose weight and reduce belly fat. According to Gram Research analysis, teens who exercised lost about 1.9 kilograms more than those who didn’t exercise, and their waist circumference shrank by nearly 3 centimeters. However, researchers noted the evidence quality is still low to moderate, meaning we need better studies to fully understand how much exercise helps and what type works best for different teens.
Key Statistics
A 2026 Cochrane systematic review of 30 randomized controlled trials involving 1,508 adolescents found that physical activity reduced body weight by an average of 1.88 kilograms compared to no exercise, with low-certainty evidence supporting this finding.
According to the 2026 Cochrane review, teenagers with obesity who engaged in physical activity reduced their waist circumference by 2.88 centimeters and body fat percentage by 2.96 percent compared to those who did not exercise.
A single study of 56 teenagers within the 2026 Cochrane review found that physical activity improved self-esteem by 0.47 units and self-efficacy by 0.58 units compared to no exercise, though this finding requires confirmation from larger studies.
The 2026 Cochrane systematic review identified very low-certainty evidence that physical activity reduced insulin resistance by 0.99 units in 256 adolescents across 6 studies, indicating uncertain effects on blood sugar control.
The Quick Take
- What they studied: Whether exercise programs help teenagers aged 10 to 19 years who have obesity lose weight and improve their health
- Who participated: 1,508 teenagers from 30 different studies across 15 countries. Most were between 10 and 17 years old and had obesity at the start of the studies. Studies were published between 2012 and 2023
- Key finding: Teens who did any type of physical activity lost about 1.9 kilograms more than those who didn’t exercise, and their waist circumference decreased by about 2.9 centimeters. Body fat percentage also dropped by about 3 percent
- What it means for you: Exercise appears to help teenagers with obesity lose weight and reduce body fat. However, the improvements are modest, and researchers say we need higher-quality studies to know which types of exercise work best and how much activity teens really need
The Research Details
This was a systematic review, which means researchers searched through many scientific databases to find all the best studies on exercise and teen obesity. They looked at studies published between 2012 and 2025 and included only randomized controlled trials, which are the gold standard in science. A randomized controlled trial means some teenagers were randomly assigned to exercise programs while others were not, so researchers could fairly compare the results.
The researchers looked at 30 studies total with 1,508 teenagers. They examined what happened when teens did physical activity for at least 12 weeks. The exercise programs varied: some were high-intensity workouts, some were moderate-intensity, and some combined different types of activity. The researchers then combined all the results using a technique called meta-analysis to see the overall pattern across all studies.
They measured several important outcomes including body weight, BMI (a measure of body size), waist circumference, body fat percentage, blood sugar levels, and mental health. They also looked at whether exercise affected how much physical activity teens did overall and their quality of life.
This research approach is important because individual studies can sometimes give misleading results by chance. By combining results from 30 different studies across multiple countries, researchers can see the true pattern of whether exercise actually helps. The systematic review also checked the quality of each study to make sure the conclusions are based on reliable evidence. This helps doctors and parents understand what we really know about exercise for teen obesity, rather than relying on one small study that might not be accurate.
All 30 studies included in this review had some methodological limitations, meaning none were perfect. The researchers noted that the certainty of the evidence was low to very low for most findings. This means while the results suggest exercise helps, we should be cautious about how much we trust these conclusions. The studies varied quite a bit in how they measured results and what types of exercise they tested, which made it harder to draw firm conclusions. Additionally, the studies were generally small, and some results were imprecise. The researchers emphasized that future high-quality studies will likely provide clearer answers.
What the Results Show
When teenagers with obesity did any type of physical activity compared to doing no exercise, they experienced modest improvements in several areas. Body weight decreased by an average of 1.88 kilograms, which is about 4 pounds. Waist circumference, which measures belly fat, decreased by 2.88 centimeters or about 1.1 inches. Body fat percentage dropped by approximately 2.96 percent.
The review also found that exercise may help with blood sugar control. Glucose levels decreased slightly, and insulin resistance (a measure of how well the body handles blood sugar) improved. However, the certainty of evidence for these findings was very low, meaning researchers are less confident about these particular results.
One interesting finding was that mental health may improve with exercise. A study of 56 teenagers found that those who exercised had better self-perception, self-efficacy (belief in their ability to succeed), and self-esteem compared to those who didn’t exercise. However, this finding came from only one small study, so more research is needed to confirm it.
When researchers compared different types of exercise against each other, such as high-intensity interval training versus moderate-intensity continuous exercise, the evidence was too uncertain to draw any conclusions. This means we don’t yet know which specific type of exercise works best for teenagers with obesity.
The review looked at many other health measures but found limited or no data on several important outcomes. Physical activity levels, blood pressure, and various fat distribution measures showed low to very low certainty evidence. The studies provided very little information about important factors like whether exercise affected hunger, overall quality of life, or whether obesity persisted into adulthood. Notably, none of the studies reported on adverse events or injuries from exercise, which is important safety information. The review also found no studies that included teenagers with disabilities, which is a significant gap since these young people may have different exercise needs and responses.
This is one of the most comprehensive reviews on this topic, updating and expanding on previous systematic reviews. Earlier reviews suggested exercise might help with teen obesity, but they had limitations in how completely they reported results and how they assessed evidence quality. This new review uses the GRADE approach, a rigorous method for evaluating how confident we should be in research findings. The findings are consistent with previous research showing that exercise provides modest benefits for weight loss in teenagers, but this review emphasizes that the evidence quality remains low to very low, meaning we need better studies to be more certain.
The researchers identified several important limitations. First, all 30 included studies had high risk of bias, meaning there were methodological problems that could have affected the results. Second, the studies varied significantly in their design, the types of exercise tested, and how they measured outcomes, making it difficult to combine results reliably. Third, the studies were generally small, which means the results may not be as precise or reliable as larger studies would be. Fourth, important outcomes were rarely measured or reported, including long-term effects, safety information, and whether weight loss persisted after the exercise program ended. Fifth, no studies included teenagers with disabilities, limiting how broadly these findings apply. Finally, the studies provided little information about real-world factors like access to exercise facilities, cultural preferences, or family support, which affect whether teenagers actually stick with exercise programs.
The Bottom Line
Based on low-certainty evidence, physical activity appears to help teenagers with obesity lose weight and reduce body fat. Current recommendations suggest that teenagers should aim for at least 60 minutes of moderate-intensity physical activity most days of the week, though the specific amount and type that works best remains unclear. Exercise should be combined with other approaches like healthy eating for best results. Parents and healthcare providers should encourage teenagers to find physical activities they enjoy, as this increases the likelihood they will stick with them. However, because the evidence quality is low, these recommendations should be considered preliminary and may change as better research becomes available.
These findings are most relevant for teenagers aged 10 to 19 years who have obesity and their parents, healthcare providers, school administrators, and policymakers. Teenagers with obesity should consider starting or increasing physical activity as part of weight management. Healthcare providers can use this information to counsel families about exercise benefits. School administrators can use this to justify physical education programs. However, teenagers with certain medical conditions, disabilities, or injuries should consult with their doctor before starting new exercise programs, as this review did not include studies on these populations. The findings may not apply equally to all teenagers since the studies were conducted in different countries with different populations.
Teenagers should expect modest changes over time rather than dramatic results. The studies reviewed lasted at least 12 weeks, and most improvements in weight and body fat appeared within this timeframe. However, the average weight loss was only about 1.9 kilograms, so teenagers should have realistic expectations. Mental health benefits like improved self-esteem may appear relatively quickly, but more research is needed on this. Long-term effects beyond the study period are unknown, so maintaining exercise habits over months and years is important for sustained benefits.
Frequently Asked Questions
How much weight can a teenager expect to lose from exercising?
Based on research reviewed by Gram, teenagers with obesity who exercise regularly can expect to lose approximately 1.9 kilograms (4.2 pounds) more than those who don’t exercise over 12 weeks or longer. However, this is a modest amount, and actual results vary by individual. Combining exercise with healthy eating produces better results than exercise alone.
What type of exercise is best for teenagers with obesity?
The 2026 Cochrane review found insufficient evidence to determine which specific type of exercise works best. Teenagers showed improvements with various activities including high-intensity interval training, moderate-intensity continuous exercise, and mixed programs. The most effective exercise is the type a teenager will actually do consistently, so choosing activities they enjoy matters most.
How long does it take to see results from exercise?
Most studies reviewed lasted at least 12 weeks, and improvements in weight and body fat appeared within this timeframe. Mental health benefits like improved self-esteem may develop more quickly. However, the changes are gradual rather than dramatic, so teenagers should maintain realistic expectations and focus on building long-term exercise habits.
Can exercise alone help a teenager lose weight?
Exercise helps but produces modest weight loss on its own. The 2026 Cochrane review found that physical activity alone resulted in an average loss of 1.9 kilograms. Combining exercise with dietary changes typically produces better results. Healthcare providers recommend a comprehensive approach including both increased physical activity and improved nutrition for more significant weight loss.
Does exercise improve mental health in teenagers with obesity?
Limited evidence suggests exercise may improve mental health. One study in the Cochrane review found that teenagers who exercised had better self-esteem, self-efficacy, and self-perception compared to those who didn’t exercise. However, only one study measured these outcomes, so more research is needed to confirm mental health benefits.
Want to Apply This Research?
- Track weekly exercise minutes and body measurements (weight and waist circumference) every 2 to 4 weeks. Set a goal of 60 minutes of moderate-intensity activity most days of the week. Record the type of activity, duration, and how you felt afterward to identify which activities you enjoy most and are most likely to continue
- Start with small, achievable goals like adding 10 to 15 minutes of activity to your daily routine. Choose activities you genuinely enjoy, whether that’s dancing, sports, walking with friends, or cycling. Use the app to log activities immediately after completing them, and celebrate weekly milestones to build motivation and habit formation
- Measure progress every 2 to 4 weeks using weight and waist circumference rather than daily measurements, which fluctuate. Track mood and energy levels alongside physical metrics to capture mental health benefits. Set monthly goals that gradually increase activity duration or intensity. Review trends over 8 to 12 weeks to see if your efforts are working, and adjust your approach if needed
This article summarizes research findings and should not replace professional medical advice. Teenagers with obesity should consult with their healthcare provider before starting new exercise programs, especially if they have existing health conditions, disabilities, or injuries. The evidence reviewed in this article is rated as low to very low certainty, meaning conclusions may change as better research becomes available. Individual results vary, and what works for one teenager may not work for another. Parents and teens should work with healthcare providers to develop personalized exercise and nutrition plans appropriate for each individual’s circumstances.
This research translation is published by Gram Research, the science division of Gram, an AI-powered nutrition tracking app.