Scientists are planning to review studies about how our genes might affect which diets work best for losing weight. Some people lose weight faster on high-protein diets, while others do better with low-carb or low-fat plans. This review will look at research studies that tested different diets in people with different genetic makeups to see if knowing your genes could help doctors recommend the perfect diet just for you. The goal is to understand whether personalized nutrition based on your DNA could be more effective than one-size-fits-all diets.

The Quick Take

  • What they studied: Whether certain genetic differences in people’s DNA affect how well they lose weight on different types of diets (high-protein, low-carb, or low-fat)
  • Who participated: This is a plan to review existing research studies with adult participants; the actual participant numbers will depend on which studies they find and include
  • Key finding: This is a research protocol (a plan for a study), not completed research yet. The researchers haven’t found their results because they’re still planning how to conduct the systematic review
  • What it means for you: In the future, this research may help doctors understand if genetic testing could help personalize diet recommendations for better weight loss results. However, this is still in the planning stages, so practical applications aren’t available yet

The Research Details

This is a protocol—essentially a detailed blueprint for how researchers will conduct a systematic review. A systematic review is like a super-thorough research project where scientists search through many existing studies on a topic, carefully evaluate their quality, and combine their findings. In this case, researchers will search five major scientific databases (PubMed, Cochrane Library, Scopus, Science Direct, and Google Scholar) to find all randomized controlled trials (the gold standard of research) that tested different diets in people with different genetic profiles. They’ll look specifically for studies that measured weight loss in adults who followed high-protein, low-carb, or low-fat diets and had their genes tested.

The researchers will carefully extract information from each study about how much weight people lost, what their metabolism looked like, and which genetic variants they had. They’ll use a standardized tool to check if each study was well-designed and trustworthy. Then they’ll organize all this information and look for patterns across studies.

For the final analysis, they plan to group studies by diet type and use statistical methods to combine results from multiple studies (called meta-analysis) to see if genetic differences predict who benefits most from each diet approach.

This systematic review approach is important because it brings together all the best evidence on a topic rather than relying on single studies that might have different results. By combining many studies, researchers can spot real patterns and get a clearer picture of whether genetics truly matter for diet success. This is especially valuable for nutrigenomics (using genes to personalize nutrition) because individual studies might show conflicting results, but a comprehensive review can help determine if the evidence is strong enough to recommend genetic testing for diet planning.

This is a protocol, so the actual quality of results isn’t yet known. However, the study design shows several strengths: they’re searching multiple databases to avoid missing studies, they’ll use a rigorous bias assessment tool, they’re pre-specifying their analysis methods (which prevents cherry-picking results), and they’ll grade the certainty of evidence using an established system. The main limitation is that the quality will depend on the studies they find—if most existing research is poorly designed, the final review will reflect that limitation.

What the Results Show

This is a protocol document, not a completed study, so there are no actual results yet. The researchers are outlining their plan to eventually answer whether genetic variants influence how well people lose weight on different macronutrient-based diets. They expect to find studies comparing weight loss outcomes in people with different genetic profiles who followed high-protein, low-carb, or low-fat diets.

Once they complete their review, they plan to present findings separately for each diet type because the effects may differ. For example, they might find that people with certain genetic variants lose more weight on high-protein diets, while others do better with low-carb approaches. They’ll also look at whether factors like how long someone followed the diet, their physical activity level, or their ancestry affected the results.

The researchers acknowledge that they expect to find significant differences (heterogeneity) across studies, which is why they’re planning to analyze each diet type separately rather than combining all results together. This careful approach helps ensure they don’t miss important patterns.

Beyond weight loss, the researchers plan to examine metabolic markers—measurements like blood sugar control, cholesterol levels, and insulin sensitivity that indicate overall health. They’ll also look at whether the benefits of genotype-based diet recommendations depend on how long people stick with the diet or how active they are. The review will examine whether ancestry (genetic background of different populations) affects how well genetic-based diet recommendations work, which is important because most nutrition research has focused on European ancestry populations.

The researchers note that while traditional calorie-restricted diets are proven to work for weight loss, newer research suggests that the type of diet (how much protein, carbs, or fat) might matter differently for different people based on their genes. Previous reviews have looked at macronutrient diets or genetic factors separately, but comprehensive reviews combining both aspects are lacking. This systematic review will fill that gap by specifically examining how genetic variants interact with different macronutrient distributions.

Since this is a protocol, the actual limitations will become clear once the review is completed. However, predictable limitations include: the quality of findings will depend on the quality of existing studies (if most studies are small or poorly designed, conclusions will be weaker); there may be very few studies examining specific genetic variants with specific diets; different studies may measure outcomes differently, making comparisons difficult; most existing research may focus on certain populations, limiting how broadly findings apply; and publication bias (studies showing positive results are more likely to be published) could skew results.

The Bottom Line

This is a research protocol, not completed research, so specific recommendations aren’t available yet. However, the future findings may eventually support: (1) Genetic testing as a tool to personalize diet recommendations—confidence level will depend on study findings; (2) Different macronutrient distributions for different people based on genetic profiles—only if strong evidence emerges; (3) Combining genetic information with other factors (activity level, preferences, health conditions) when choosing a diet approach. Currently, standard advice remains: focus on calorie balance, choose whole foods, and pick a diet you can stick with long-term.

This research will eventually matter most to: people struggling with weight loss who want personalized approaches; healthcare providers and dietitians looking for evidence-based tools; people interested in precision medicine; and researchers studying nutrigenomics. It may be less relevant for people who have already found a diet that works well for them. This research is NOT yet ready for practical application—it’s still in the planning stage.

No timeline applies yet since this is a protocol. Once the systematic review is completed (typically 1-2 years for this type of project), it will take additional time for findings to be translated into clinical guidelines and practical tools. Real-world implementation of genetic-based diet recommendations would likely take several more years after that.

Want to Apply This Research?

  • Once this research is completed and validated, apps could track: weekly weight changes stratified by reported macronutrient distribution (% protein, carbs, fats), genetic variant information (if user has genetic testing), and metabolic markers like energy levels and hunger patterns to see if personalized macronutrient ratios based on genetics improve outcomes compared to standard recommendations
  • Future app feature could allow users to input genetic test results (if available) and receive personalized macronutrient targets (e.g., ‘Your genes suggest trying 35% protein, 35% carbs, 30% fat’ vs. standard recommendations), then track adherence and weight loss to see if the personalized approach works better for them individually
  • Long-term tracking could compare weight loss and metabolic improvements when following genotype-based macronutrient recommendations versus standard diet approaches over 12-24 weeks, with monthly check-ins on adherence, energy levels, hunger, and metabolic markers to determine if personalization provides real-world benefits

This article describes a research protocol (a plan for a study), not completed research with actual results. The systematic review has not yet been conducted, so no definitive conclusions about genetic-based diet recommendations can be made at this time. Genetic testing for diet personalization is not yet standard medical practice and should only be pursued under professional guidance. Before making significant dietary changes, consult with a healthcare provider or registered dietitian, especially if you have existing health conditions, take medications, or have a history of eating disorders. This information is for educational purposes only and should not replace professional medical advice.