According to Gram Research analysis, a 2026 randomized controlled trial of 223 adults found that people with genes predisposing them to weight gain lost just as much weight through structured dieting as those with protective genes. Participants receiving dietary coaching lost an average of 1.51 kg in six months, while genetic risk didn’t affect this outcome, suggesting your genes don’t prevent successful weight loss through diet.
A new study challenges the idea that your genes determine whether you can lose weight through dieting. Researchers at Nature Communications studied 223 overweight adults and found that people with genes that typically make weight gain easier still lost significant weight when they followed a structured diet plan. The study suggests that even if you’re genetically predisposed to gain weight, you can still successfully lose it with proper dietary guidance—your genes aren’t your destiny when it comes to weight loss.
Key Statistics
A 2026 randomized controlled trial published in Nature Communications of 223 overweight adults found that structured dietary coaching reduced BMI by 1.51 kg/m² in six months, with no difference in weight loss response based on genetic predisposition to obesity.
In the GENEROOS study of 223 participants, people in the top 5% of genetic obesity risk had baseline BMIs 3.0 kg/m² higher than those in the bottom 5%, yet both groups lost weight equally well when given structured dietary intervention.
A 2026 study of 223 adults found that genetic polygenic scores for obesity risk did not predict response to a six-month dietary intervention, with no statistically significant interaction between genetic risk and weight loss outcomes.
The Quick Take
- What they studied: Whether people with genes that make them prone to weight gain respond differently to a diet program than people without those genes.
- Who participated: 223 overweight or mildly obese adults (average age 51, mostly women) selected from the extremes of genetic risk—some with genes that strongly increase weight gain risk, others with genes that protect against it.
- Key finding: People on the structured diet lost an average of 1.51 kg (3.3 pounds) in six months, while the control group stayed about the same. Importantly, people with high-risk weight-gain genes lost just as much weight as those with protective genes.
- What it means for you: If you’ve worried that your genes make dieting pointless, this research suggests otherwise. Your genetic predisposition to weight gain doesn’t prevent you from losing weight through diet—though this study was relatively small and short-term, so larger, longer studies would strengthen this conclusion.
The Research Details
This was a randomized controlled trial called GENEROOS, which is the gold standard for testing whether something actually works. Researchers identified 38,621 people who had their DNA tested, then selected 223 participants from the genetic extremes—some with genes that strongly increase weight gain risk and others with protective genes. Half received six months of structured dietary coaching (learning about nutrition and getting personalized guidance), while the other half received no intervention. Everyone’s weight was measured at the start and after six months.
The researchers used something called a ‘polygenic score’—basically a genetic report card that adds up all the tiny genetic variations linked to weight gain. This score can predict who’s more likely to struggle with weight, but the study tested whether this prediction actually changes how well someone responds to a diet program.
This approach is important because it directly tests a real-world question: should doctors use genetic testing to decide who gets diet help? If genes determined diet success, people with high-risk genes might need different treatment. But the study found they don’t.
Many people believe their genes are their destiny when it comes to weight. This study matters because it tests that belief directly in a controlled way. If genetic risk scores could predict who would succeed or fail at dieting, doctors could use them to personalize treatment. But finding no difference means current genetic tests shouldn’t be used to decide who gets diet help—everyone benefits similarly.
This study has several strengths: it’s a randomized controlled trial (the best type of study design), it was published in Nature Communications (a highly respected journal), and it used actual genetic data rather than assumptions. However, the sample size of 223 is relatively small, and the study only lasted six months, so we don’t know if the pattern holds long-term or in larger populations. The researchers themselves note that modest genetic effects might exist but weren’t detected due to sample size.
What the Results Show
The diet intervention worked: people who received structured dietary coaching lost an average of 1.51 kg (3.3 pounds) over six months, while the control group essentially maintained their weight (losing only 0.01 kg on average). This difference was statistically significant, meaning it’s very unlikely to be due to chance.
The crucial finding was that genetic risk didn’t change this outcome. People with genes that strongly predispose them to weight gain lost just as much weight as people with protective genes. The study found no statistical interaction between genetic risk and diet response, meaning the diet worked equally well regardless of genetic predisposition.
At baseline, the genetic differences were real and measurable: people in the highest genetic risk group had BMIs that were 3.0 kg/m² higher than those in the lowest risk group. But when it came to responding to the diet intervention, these genetic differences didn’t matter. Both groups benefited similarly from the structured dietary coaching.
The study didn’t report detailed secondary outcomes like changes in specific nutrients, exercise patterns, or metabolic markers. The focus was specifically on whether genetic risk modified the weight loss response. The researchers did note that the intervention was ‘structured dietary coaching,’ suggesting it involved personalized guidance rather than just a generic diet plan, which may have contributed to its effectiveness.
This finding aligns with growing evidence that lifestyle interventions work broadly across different genetic backgrounds. Previous research has shown that genes influence weight, but genes aren’t deterministic—environmental factors like diet and exercise matter enormously. This study adds to that picture by showing that genetic risk scores don’t predict who will succeed at dieting. It challenges the emerging field of ‘precision nutrition’ that assumes genetic testing should guide dietary recommendations.
The study is relatively small (223 participants) and short-term (six months), so it can’t rule out genetic effects that might appear in larger or longer studies. The participants were mostly women (74.9%) and had an average age of 51, so results might differ in younger people or men. The study only tested one type of intervention (structured dietary coaching), so other diet approaches might show different genetic patterns. Finally, the researchers selected people from the genetic extremes (top and bottom 5%), which might not represent typical populations where genetic effects could be more subtle.
The Bottom Line
If you’re overweight or obese, pursue dietary intervention regardless of your genetic background. Structured dietary coaching appears effective for weight loss across all genetic risk levels. You don’t need genetic testing to decide whether to try dieting—the evidence suggests it will likely help you. Confidence level: Moderate (based on a single RCT of moderate size; larger studies would increase confidence).
Anyone worried that their genes make weight loss impossible should find this encouraging. People considering genetic testing for diet planning should know that current genetic scores don’t predict diet success. Healthcare providers considering using genetic risk scores to decide who gets diet help should know this study suggests that approach isn’t necessary—everyone benefits similarly. This doesn’t apply to people with specific genetic conditions affecting metabolism (like rare genetic syndromes), which weren’t studied here.
In this study, meaningful weight loss appeared within six months (averaging 3.3 pounds). However, this is relatively short-term. Realistic expectations: you might see initial weight changes within weeks, but six months is a reasonable timeframe to assess whether a dietary intervention is working for you. Longer-term success (beyond six months) wasn’t measured in this study.
Frequently Asked Questions
Can you lose weight if you have genes that make you gain weight easily?
Yes. A 2026 study of 223 adults found that people with high genetic obesity risk lost the same amount of weight through structured dieting as those with protective genes—averaging 1.51 kg in six months. Your genes influence weight, but they don’t prevent diet success.
Should I get genetic testing to see if dieting will work for me?
Probably not, based on current evidence. This study found that genetic risk scores don’t predict who will succeed at dieting. Everyone in the study benefited similarly from dietary intervention regardless of genetic background, suggesting genetic testing isn’t necessary to decide whether to try dieting.
How much weight can I expect to lose with structured dietary coaching?
In this six-month study, participants lost an average of 3.3 pounds (1.51 kg) with structured dietary coaching, while controls lost essentially nothing. Results vary individually, but this represents a realistic short-term expectation with professional dietary guidance.
Does genetic predisposition to obesity mean I can’t lose weight?
No. This 2026 randomized trial of 223 adults showed that genetic predisposition to higher BMI doesn’t prevent weight loss through diet. People with genes strongly linked to weight gain responded to dietary intervention just as well as those with protective genes.
What type of diet intervention worked best in this study?
The study tested ‘structured dietary coaching’—personalized guidance rather than a generic diet plan. The intervention reduced BMI by 1.51 kg/m² in six months. The study didn’t compare different diet types, so it’s unclear if specific diets work better than others.
Want to Apply This Research?
- Track weekly weight and dietary adherence (percentage of days following the structured plan) over a 12-week period. This allows users to see if they’re responding to dietary intervention similar to study participants, without needing genetic testing.
- Users can implement ‘structured dietary coaching’ by using the app to log meals, receive personalized nutrition feedback, and track progress against specific dietary goals. The study’s success came from structured guidance, not from genetic testing, so the app should emphasize consistent tracking and feedback.
- Establish a baseline weight and dietary pattern in week 1, then monitor weekly weight trends and dietary consistency. After 6-8 weeks, assess whether weight is trending downward. If not, the app should prompt users to review dietary adherence and consider adjusting the approach—not because of genetics, but because individual responses to specific diets vary.
This research suggests that genetic risk scores don’t predict short-term weight loss response to dietary intervention in overweight adults. However, this is a single study of moderate size lasting only six months. Genetics do influence weight, and individual responses to diet vary considerably. Before making changes to your diet or weight loss plan, consult with a healthcare provider or registered dietitian, especially if you have underlying health conditions, take medications, or have a history of eating disorders. This research does not apply to people with specific genetic conditions affecting metabolism. Genetic testing for diet planning is not currently recommended based on this evidence.
This research translation is published by Gram Research, the science division of Gram, an AI-powered nutrition tracking app.