Scientists are discovering that people’s genes may affect how well they respond to different weight loss strategies. A new review of research studies found that over 20 genes influence whether someone loses weight through diet and exercise changes. Some people might do better with one type of diet while others succeed with a different approach, based on their genetic makeup. While this “personalized” approach sounds promising, current studies show mixed results about whether tailoring weight loss plans to someone’s genes actually works better than standard advice for everyone. Researchers say we need more advanced studies to figure out if genetic testing can truly help people lose weight more effectively.

The Quick Take

  • What they studied: Whether weight loss plans should be customized based on a person’s genes, and if this approach works better than giving everyone the same advice
  • Who participated: This was a review of multiple research studies involving overweight and obese people. The exact number of total participants wasn’t specified, but the review examined many randomized controlled trials (the gold standard type of study)
  • Key finding: Scientists found that more than 20 genes affect how people respond to lifestyle changes for weight loss. People with different genes may lose different amounts of weight on the same diet and exercise plan. However, studies comparing personalized genetic plans to standard plans show mixed results—it’s not yet clear if knowing your genes actually helps you lose more weight
  • What it means for you: Genetic testing for weight loss might become available in the future, but right now there’s not enough proof that it works better than regular weight loss advice. For now, focus on healthy eating and exercise habits that work for you personally, rather than waiting for genetic testing. Talk to your doctor before making major diet changes

The Research Details

This was a review article that looked at many different research studies about weight loss and genetics. The researchers examined randomized controlled trials (RCTs), which are considered the most reliable type of study because they randomly assign people to different groups to test if one approach works better than another.

The scientists searched for studies that tested whether customizing weight loss plans based on someone’s genes worked better than giving everyone the same plan. They looked specifically at how different genes, like FTO and MC4R, affected whether people lost weight when they changed their diet and exercise habits.

The review found that researchers have identified over 20 genes that seem to influence how well someone responds to weight loss efforts. This suggests that genetics do play a role in weight management, but the studies comparing personalized genetic plans to standard plans showed very different results from each other.

Understanding how genes affect weight loss is important because it could eventually help doctors give people more effective, personalized advice. If we know which genes someone has, we might be able to predict which diet and exercise approach will work best for them. This could help more people successfully lose weight and prevent diseases like diabetes and heart disease. However, we need to make sure the science is solid before recommending genetic testing to everyone

This was a review of existing studies rather than a new experiment, which means it summarizes what other scientists have found. The researchers noted that the studies they reviewed showed “considerable heterogeneity,” which is a fancy way of saying the results were very different from each other. This makes it harder to draw clear conclusions. The review is honest about the fact that we don’t yet have enough evidence to say whether personalized genetic plans are actually better than standard advice

What the Results Show

The main finding is that scientists have identified more than 20 genes that appear to influence how people respond to weight loss efforts. Two genes that have been studied the most are called FTO and MC4R. These genes seem to affect how much weight different people lose when they follow the same diet and exercise plan.

The research shows that there are real “gene-lifestyle interactions,” which means your genes and your lifestyle choices work together to determine your weight. In other words, the same diet that helps one person lose 20 pounds might only help another person lose 5 pounds, partly because of their different genes.

However, when researchers actually tested whether giving people personalized plans based on their genes worked better than giving everyone the same plan, the results were inconsistent. Some studies showed personalized plans were better, while others showed no real difference. This is why scientists say we still don’t have a clear answer about whether genetic testing actually helps people lose weight more successfully.

The review also noted that future research needs to look at how multiple genes work together, not just individual genes. Scientists are also interested in using advanced computer programs (machine learning) to combine genetic information with other biological data to create better personalized plans. The researchers emphasized that this field is still developing and that more sophisticated studies are needed

This research builds on earlier discoveries that genes affect weight and metabolism. Previous studies had already shown that genetics influence how much people weigh and how their bodies process food. This review adds to that knowledge by specifically looking at whether knowing someone’s genes can help predict which weight loss strategy will work best for them. The field is moving toward more personalized medicine, but this review shows we’re still in the early stages of understanding how to use genetic information for weight loss

The biggest limitation is that the studies being reviewed showed very different results from each other, making it hard to draw firm conclusions. The review doesn’t tell us the exact number of people studied across all the research. Additionally, most of these studies are still relatively new, so we don’t have long-term data about whether personalized genetic plans help people keep weight off over many years. The research also mostly focuses on a few specific genes, when in reality, weight is influenced by hundreds of genes working together

The Bottom Line

Based on current evidence (moderate confidence): Continue following standard healthy lifestyle advice—eating nutritious foods and getting regular exercise—because this works for many people. Don’t spend money on genetic testing for weight loss yet, as there’s not enough proof it helps. If you’re interested in personalized nutrition, talk to a registered dietitian who can help you find an eating plan that fits your lifestyle and preferences. In the future, genetic testing might become a useful tool, but we need more research first (low to moderate confidence)

This research is relevant to anyone struggling with weight loss, especially people who have tried standard diet and exercise advice without success. It’s also important for doctors and nutritionists who want to stay updated on new approaches. However, people shouldn’t feel pressured to get genetic testing right now. This research is also relevant to people with a family history of obesity or weight-related diseases. Those who shouldn’t rely on this yet: people looking for a quick fix or magic solution—genetics is just one piece of the weight loss puzzle

If you follow healthy eating and exercise habits, you might see weight loss results within 4-8 weeks. However, sustainable weight loss usually takes months to years. If genetic testing becomes available and proven effective in the future, it might help you see results faster by matching you with the best approach for your body. For now, focus on consistency rather than waiting for personalized genetic plans

Want to Apply This Research?

  • Track your weekly weight, daily food intake, and exercise minutes. Also note which types of foods and activities seem to work best for you personally. This personal data is more useful right now than genetic testing would be
  • Use the app to experiment with different eating styles (like higher protein, lower carb, Mediterranean diet, etc.) and track which one helps you feel best and lose weight most consistently. Record your energy levels, hunger, and mood with each approach to find your personal ‘best fit’ diet
  • Over 8-12 weeks, try different combinations of diet and exercise while tracking results. Look for patterns in what works for YOUR body specifically. This personalized approach based on your own experience is more evidence-based right now than genetic testing. Share these findings with your doctor or dietitian

This review summarizes research about genetics and weight loss, but genetic testing for weight loss is not yet proven to be more effective than standard healthy lifestyle advice. This information is educational and should not replace advice from your doctor or registered dietitian. Before making any major changes to your diet or exercise routine, especially if you have health conditions or take medications, consult with your healthcare provider. Genetic testing should only be done under medical supervision. Weight loss is complex and involves genetics, environment, behavior, and medical factors—no single test or approach works for everyone.