Transcript for At-home tests claim to analyze your genes to determine the best diet for you
We are turning now to our home consumer lab. This morning we'll break down a new health trend using your genes to determine your diet? ABC's Becky Worley has that story. Reporter: What's it feel like to lose weight on weight watchers? Dieting, lose 20 pounds for $20. Hundreds of plans. I tried everything. I had the low carb eating. I had the green juicing, smoothie, cleanses. Reporter: For this woman none seemed right for her. I felt I was in a war with food. Reporter: She turned to habit, an at home test that promises a personalized nutrition plan but doesn't promise weight loss. I wanted to find a way to eat that was sustainable, that was healthy. Reporter: It has a few elms, swab your cheek, measure your waist and submit a few blood samples and analyze DNA, metabolism and biomarkers they say impact your body's ability to process food. Then they create a personalized profile to help eaters make healthy choices. Based on the results test takers are assigned to one of seven different profiles like protein seeker, fat seeker and a profile for people who need to slow their me tab limps. She was assigned a grain lover's dream. I was a rank seeker which meant that I can have up to 50 to 60% of my calories from carbs. Was that good news? Do you love carbs? I love carbs. Yeah, I love carbs. Reporter: The company says while weight loss isn't promised it's possible. They say weight loss with habit is designed for no more than half a pound to two pounds a week. After eight weeks she hasn't lost weight but inches. I'm more energized and active. My clothes are starting to fit differently on me. Reporter: Other at home testing services offer personalized diets based on your DNA like this from orig3n and this from dnafit that runs 199. Habit is more expensive and includes a metabolic test and access to their app and phone-based coaching and costs $309 and isn't covered by most insurance plans. But it's still early days. While studies are ongoing so far little evidence that profiling your DNA by itself leads to significant weight loss or healthier outcomes. Mine is protein seeker. Reporter: The founder of habit says his company's program is worth it. Six months later I lost 25 pounds and felt better than I had felt in years. Reporter: He tested positive for the obesity gene and has to really watch his fat intake. How does this differ from going to see a nutritionist? Depending you may get more of a standard or generic recommendation but based on your DNA, blood work and metabolism. More refined and very specific recommendation. Reporter: For "Good morning America," Becky Worley, Oakland, California. That's really good. Dr. Jennifer Ashton is back. Yes, high dear. Watching that piece with you, you have a degree in nutrition. Tell us what you think of these dn. A-based diets. The evidence is not there yet. These studies need much better methodology. They're in their early stages of investigation and little evidence to support it and according to the academy of nutrition and dietetics newt tree genetic dietary based practices are not recommended. What about those people in the piece who say they felt they had success -- Placebo works 30% of the time. In general if you focus on food, good things are going to happen and people like a personalized, individualized approach to their eating and that really speaks to it. This is just an example as a nutritionist as a physician of the types of food I recommend in a day. If you eat like this, you will feel and look good. And drink lots of water we learned from Tom Brady. Exactly, that's right. Dr. Jen. I'll drink to that.
This transcript has been automatically generated and may not be 100% accurate.