At-home DNA tests have gained popularity, offering insights into ancestry, health risks, and family planning. Some individuals are turning to genetic testing to enhance their fitness levels, drawn by studies suggesting that DNA influences the effectiveness of diets. This article explores the accuracy and reliability of genetic testing for weight loss, examining its potential benefits and limitations.
What is a DNA Diet Test?
A DNA diet test is similar to other at-home DNA tests used for ancestry research or health information. Customers provide a DNA sample, which is then analyzed in a lab to determine how their body processes and reacts to specific nutrients. This information can be used to make informed decisions about nutrition and achieve health goals.
Many factors influence weight loss, including metabolism and activity levels. A DNA diet test examines genes to determine how effectively nutrients are processed, utilized, and eliminated. This information can help individuals tailor their diets to meet their unique nutritional needs.
Potential Benefits of Genetic Nutrition Testing
Genetic nutrition testing can improve health on many levels. It helps individuals develop healthy eating plans that provide their bodies with the necessary foods and supplements based on their DNA. Additional benefits include:
- Creating personalized diet and exercise plans to increase the chances of weight loss
- Identifying potential health risks, such as diabetes, and adjusting the diet accordingly
- Learning about food intolerances to avoid digestive problems
- Understanding how the body tolerates caffeine and other chemicals that can affect health
- Identifying risk levels for certain conditions and using genetic nutrition for prevention
- Finding the source of symptoms like lactose intolerance or food allergies
- Improving injury recovery by boosting the immune system with proper nutrition
- Identifying micronutrient deficiencies
- Reducing stress through better nutrition
- Improving sleep quality by eating better
It's important to consult with a physician about any health concerns revealed by DNA tests. While DNA testing can calculate the risk level for certain health issues, it does not predict whether a condition will develop. Sharing this information with a physician can guide preventive treatment plans.
Read also: Unlock Your Fitness Potential with Genetic Testing
How Reliable Are DNA Diet Tests?
While DNA tests are generally considered highly accurate, no testing method is 100% accurate. The science of DNA sequencing has become more accessible, and the process of reading genetic markers is well-tested. However, inaccuracies can occur due to sample contamination or errors in the lab.
Sample Contamination
Most DNA diet test kits require a cheek swab. If instructions are not followed correctly or the sample is contaminated by external factors, the test results may be compromised.
Unaccredited Laboratory
Errors can occur at any lab, but using an unaccredited lab increases the risk of inaccuracies. When selecting a lab for nutrition genetic testing, it's crucial to choose one that is accredited and experienced.
Variant Analysis
Different laboratories may analyze different variants of the same gene, leading to seemingly conflicting results. If one lab tests for a smaller range of variants than another, the conclusions may differ.
Is DNA Diet Testing for You?
Genetic nutrition testing is easy, simple, and generally accurate. It can provide valuable information about individual nutritional needs and help maintain a healthy weight. If considering a DNA diet test, it's important to follow all instructions and use a reliable, accredited company for sample analysis.
Read also: Unlocking Your Diet with Genetic Testing
MyPhenome Test
The test, MyPhenome, was developed by researchers at the Mayo Clinic and was licensed last year by a company called Phenomix Sciences. It costs $350 and must be ordered by a health care provider.
Dr. Acosta points out that these medications aren’t cheap. They’re not always covered by insurance, and if they are, they may come with a high copay.
In a recent small study of 84 people enrolled in a weight loss registry at the Mayo Clinic, researchers ran the test on stored blood or saliva samples. “We do need to test these in a randomized, double blinded, placebo-controlled trial that we have done for other medications. That’s the highest gold standard,” Acosta said. “But at this point, we can say that these outcomes were in patients who were blinded to the results as well as the investigation,” he added, meaning they didn’t know whether they were hungry gut-positive or -negative while they were using the drug.
The Role of Genetics in Weight Loss
Research suggests that 40 to 70 percent of body mass index (BMI) is affected by genetic factors. Genetic testing can reveal how well the body processes macronutrients like carbohydrates, fats, and proteins. For example, if a test indicates difficulty processing carbs, a low-carb diet may be recommended.
It's important to remember that genetic predispositions to obesity do not guarantee weight gain. They simply mean that maintaining a healthy weight may require more effort.
Read also: Comprehensive Guide to Hormone Testing
The DIETFITS Study: Challenging the Genetic Diet Match
Despite earlier studies suggesting that genetic variants predict weight loss success on low-carbohydrate or low-fat diets, the DIETFITS study found no significant difference in weight loss between overweight people on diets that "matched" their genotype and those on diets that didn't.
The study, published in the Journal of the American Medical Association, randomly assigned 609 overweight adults to either a healthy low-fat or healthy low-carb diet. After 12 months, there was virtually no difference in weight loss between the two groups. Further analysis of weight loss based on genetic variants also showed no significant difference between participants matched or mismatched to their diet assignment.
Christopher Gardner, co-author of the study, acknowledged that the results did not replicate his earlier findings and emphasized the importance of replication in scientific research.
Alternative Perspectives on Genetic Testing for Weight Loss
While the DIETFITS study challenges the notion of genetically matched diets, some companies in the DNA/diet industry maintain that DNA, combined with other factors like blood biomarkers, can inform personalized dietary recommendations. Others argue that genes beyond those examined in the DIETFITS study can contribute to weight loss and that genetically matched diets can lead to greater weight loss.
Some studies have found that people who adapted diet and exercise to their genetic profile lost two to three times more weight than those following generic programs, illustrating how gene insights can steer daily calorie balance.
Ultimately, it's important to consider that emotional, economic, metabolic, social, and other factors can significantly impact someone’s chance of losing weight, potentially overshadowing the effect of genes.
The Importance of Lifestyle Factors
While genetic testing may offer insights into individual nutritional needs, it's crucial to prioritize core lifestyle changes for weight management. These include:
- Balanced calorie intake
- Consistent exercise
- Professional guidance
Even if a DNA test flags "slow metabolism" genes, focusing on these lifestyle factors remains the most impactful strategy.
The Role of Metabolism Genes
Genes influence factors like the number of mitochondria, brown-fat activity, and hunger hormones, but their effect is usually modest compared with lifestyle. For example, FTO variants may raise appetite by approximately 100 kcal, while UCP1 variants may reduce daily energy expenditure by about 50 kcal in cold conditions.
Studies show that prioritizing protein to 1.6 g/kg lean mass boosts thermic effect of food by about 60 kcal per day.
When to Suspect a Genetic Cause of Rapid Weight Gain
Most weight gain is environmental, but certain red flags may suggest rare genetic or endocrine disorders. These include:
- BMI jumps two standard deviations before age five
- Children exceeding the 99th BMI percentile before kindergarten
- Hyperphagia with no satiety
- Obesity plus developmental delay
- BMI gain despite growth-hormone deficiency treatment
- Family history across generations of severe obesity starting in childhood
In such cases, gene panel testing may be warranted.
Objective Blood Tests and Evidence-Based Medications
Objective blood tests and evidence-based medications often have a stronger impact on weight than current consumer genetics. These include:
- TSH testing for hypothyroidism
- HbA1c testing for insulin resistance
- GLP-1 receptor agonists for appetite control
- Liver enzyme testing for NAFLD
- Cortisol testing for Cushing’s syndrome
Limitations of Direct-to-Consumer Genetic Tests
Direct-to-consumer genetic tests can be expensive, difficult to interpret, and challenging to translate into practical recommendations. They may lead to rigid rules around food, inciting fear rather than empowerment. Additionally, these tests make predictions based on population averages that don’t account for individual variation.
Raw genetic information is difficult to interpret, and third-party interpretation services may lead to confusion and fear. For example, if a test reveals a SNP linked to obesity, individuals may assume they have no control and will automatically develop a weight problem, decreasing motivation for lifestyle interventions.
Alternative Strategies for Weight Loss
Rather than relying solely on genetic testing, individuals can focus on well-validated, inexpensive strategies that can be personalized to their needs. These include:
- Intermittent fasting: Research suggests that intermittent fasting can lead to significant weight loss for people with excess weight. Obese adults lost an average of 12 pounds in eight weeks when fasting days were alternated with days of eating freely.
- Exercise: Resistance training and cardiovascular exercise are both beneficial for weight loss and overall health.
- Gut health: Addressing leaky gut and promoting a healthy gut microbiome can improve weight loss efforts.
Steps to Improve Gut Health for Weight Loss
- Quick Gut Reset: Start with a modified fast for 2-4 days.
- Gut-Healthy Elimination Diet: Follow a diet like the Mediterranean diet for a couple of weeks or months.
- Eat Regularly: Avoid grazing and eat every 4 hours or so.
- Address Lifestyle Factors: Prioritize sleep, physical activity, and stress management.
- Consider Probiotics: Probiotics can help support a healthy gut by improving the balance of microbes, reducing inflammation, and modulating the immune system.
- Reintroduce Foods: After a period of elimination, gradually reintroduce foods while monitoring symptoms.