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How to Use DNA Tests to Help Clients Hit Weight Goals

How to Use DNA Tests to Help Clients Hit Weight Goals

As a trainer, it’s important to stay up to date on all the latest research and trends in weight loss and fitness. Your clients come to you for expertise and advice, and they’ve probably already asked about genetic testing. 

It comes as no surprise to most people, especially those who have long struggled with weight, that genes at least partly determine our ability to maintain a healthy weight. 

If you can help your client make better, more personalized choices for losing weight, why not? DNA-based fitness and nutrition coaching is becoming more popular with clients. Learn about how these tests can inform an individual’s weight goals, workout routine, and diet. 

How Genes Affect Weight 

Genes are complicated. They interact with each other and are influenced by environmental factors. So, determining which genes impact weight is difficult. Researchers have pinpointed hundreds of genes that play some role in obesity, weight, weight loss, and weight maintenance in a variety of ways. 


One example of how genetics affects weight is through the production of hormones. These are small signaling molecules that regulate all kinds of functions in the body. Leptin, for instance, is a hormone that signals when you feel full. It tells you to stop eating. Genes that limit leptin can lead to obesity. Other hormones impacted by genes, that in turn affect weight, include insulin and ghrelin (1).

Obesity Risk

A recent study found that by looking at multiple genes in an individual’s DNA, overall risk for obesity can be determined. This includes many genes and mutations with a lot of different effects. In some people, they all add up to a significant risk of being overweight or obese. In others, they add up to a tendency to be thin (2).

These are just a couple of examples of the complex ways genetics impact weight. Other factors related to genes that determine a person’s weight or ability to maintain a healthy weight include the following:

  • Appetite
  • Metabolism
  • Cravings for food
  • Tendency to eat when stressed
  • Responses to exercise
  • Distribution of body fat 

There are even genetic differences in how big of an impact genes have on weight. For some people, genetics accounts for up to 80 percent of a tendency to be overweight, while for others it is much lower (3). And, some genes make people more susceptible to post-workout muscle soreness, or DOMS, which can trigger a resistance to exercise. 

Genetic Testing and Weight Management – What DNA Tests Can Tell You

There is no one-size-fits-all solution to maintaining a healthy weight or losing extra pounds. Everyone is different, in part because of our genetics. An at-home DNA test is more affordable than ever and people are increasingly interested in finding out how their genes impact their weight loss. They also want to know how that information can help them meet weight and health goals more effectively and easily. 

Before getting into DNA testing with clients, make sure you understand what the results tell you. 

Weight Loss Tendency

One test you’ll commonly see in fitness and health DNA tests is weight loss tendency. This looks at several genes to estimate a person’s ability to lose weight when eating a healthy diet and exercising regularly. There are three possible genotypes: 

  • Normal. This result means a client should reasonably expect to lose or maintain weight on a typical workout schedule and with a healthy diet. If they comply with the program, they should hit their goals. 
  • Below average. With this result, you have a client who will find it more difficult to lose weight and keep it off over the long-term. 
  • Low. For these clients, it is very challenging to lose weight and maintain it. 

Fat Loss Response to Cardio

Cardiovascular exercise is so important for overall health, but not everyone responds the same in terms of fat and weight loss. Women, in particular, have a predictable response to cardio based on their genotypes, which include: 

  • Enhanced. Your enhanced clients can lose a significant amount of fat tissue from cardiovascular training. 
  • Normal. With a normal genotype, your clients will need to work a little harder and longer at cardio to lose fat. 

Body Composition and Strength Training

As trainers, we encourage clients to do strength training for health and fitness benefits. Strength training also supports weight loss and maintenance by shifting body composition from more fat to more muscle. The response to this kind of training varies by genotype:

  • Enhanced. A lot of athletes and bodybuilders have this genotype. They lose fat and gain muscle readily with strength training sessions. 
  • Normal. For a normal genotype, strength training is still important, but it won’t deliver results as quickly or noticeably. 
  • Below average. A client with a below average result will really struggle to lose fat and gain muscle unless they do more challenging and frequent strength training. 

Intrinsic Motivation and Impulsivity 

DNA tests can also tell you something about how motivated an individual is to workout and how likely they are to indulge in too much food, alcohol, or other destructive behaviors. These tendencies impact weight loss because they influence the degree to which a person will stick with a healthy wight-loss program. 

For instance, a DNA result may show your client has a “less likely” to be motivated genotype. This means they may resist training programs or struggle to stick with them. On the other hand, a “less likely” genotype for addictive and impulsive behaviors means they are less susceptible to indulge in binge eating or drinking. This makes it easier to stick with a personalized nutrition plan for weight loss. 

Using Test Results for Weight Loss and Maintenance

Results of genetic tests for weight and fitness are not destiny. Help your clients consider them more as risk factors. For instance, a low weight loss tendency genotype does not mean a client will be obese and can’t lose weight. It may, however, put them at a greater risk of being overweight or obese. 

Genetic Testing and Weight Management Depends on Exercise

Regardless of any client’s specific DNA results, they need to exercise regularly. Different results, however, can inform how you plan their training programs. Unfortunately for those with low and below average genotypes, they will have to work harder than those in the normal range. 

Here are some general guidelines and tips for clients in the lower genotype ranges for several measures: 

  • Weight loss tendency. For those in the low or below average category for this measure, plan for a minimum of 150 to 200 minutes of vigorous cardiovascular exercise per week, but up to 300 minutes. Those in the low category should work out at least five days a week and as many as seven. 
  • Fat loss response to cardio. To boost fat loss for “normal” clients, include more high-intensity interval training and mix in bodyweight training with cardio workouts. Increase their frequency and intensity of workouts when they hit plateaus. 
  • Body composition response to strength training. Those clients in the normal category need strength training two days a week at least. Push heavier weights to increase muscle growth and boost metabolism. In the below average category, heavier lifting is also important. These clients will also benefit from at least one day of power training per week. 

It Also Depends on Diet

Diet is essential for all your clients trying to lose or maintain weight, but it takes on crucial importance for those in lower genotypes. For those who struggle to lose weight, make stricter diet plans, count calories, use tracking apps, and work on portion control. 

Clients who struggle with motivation or impulse control can easily derail their diets. External motivation and encouragement are beneficial. Managing stress, keeping binge foods out of the house, and eating mindfully are also useful for avoiding impulsive eating and bingeing. 

Believe it or not, high motivation and poor impulse control can be a potentially damaging combination. Highly motivated clients may stick with a routine and even go beyond it, eating too little. Addictive behaviors and impulse can lead them to work out too much. This can result in injuries and dangerously rapid weight loss

Are There Any Downsides to Using Genetic Testing for Weight Maintenance?

Genetic testing and DNA-based weight management plans are imperfect. There are some downsides to the potential benefits of a genetic-based tool. Before starting a genetic test with any client, talk to them about what it means, what it can tell you, and any limitations. 

High Expectations That Lead to Disappointment

A downside to using DNA tests for weight loss is that clients may have unreasonable expectations that lead to disappointment. Before beginning a genetic-based program with a client, make sure they understand that this won’t be a quick fix. It’s about more than just going on a low-carb diet or a low-fat diet. They will still need to put in the effort to eat well and get plenty of physical activity. 

Being Overweight as Destiny

Another problem that may arise is the hopelessness some clients may feel when they get certain results. A client may learn that their DNA is working against them, that losing or maintaining weight is more challenging than for other people. They may be tempted to give up, to assume that they are destined to be overweight. 

Skating by on DNA Results

The opposite may also happen. You may get a client with good results indicating they tend to be skinnier and are less likely to be overweight. Their genes are in their favor in this respect, but you know that they still need to make healthy food choices and be active for optimal health. There is a risk that these clients will see their results as an excuse to cut back on exercise or to be more relaxed about diet and junk food. 

Genetic testing for fitness, weight loss, and other health measures is likely to become even more common. As a trainer, it’s up to you to stay informed about these developments and be prepared to answer client questions and concerns about them. 

Are you ready to add DNA coaching to your list of client services? The ISSA now offers a DNA-Based Fitness Coach course for certification. 



  1. Drabsch, T. and Holzapfel, C. (2019, March). A Scientific Perspective of Peronalised Gene-Based Dietary Recommendations for Weight Management. Nutrients. 11(3), 617-29. Retrieved from
  2. Riveros-McKay, F., Mistry, V., Bounds, R., Hendricks, A., Keogh, J., Thomas, H., Henning, E., Corbin, L., O’Rahilly, S., Zeggini, E., Wheeler, E., Barroso, I., and Farooqi, I. (2019, January 24). Genetic Architecture of Human Thinness Compared to Severe Obesity. PLOS Genetics. 15 (1): e1007603 DOI: 10.1371/journal.pgen.1007603, Retrieved from
  3. Harvard Health Publishing. Harvard Medical School. (2019, June 24). Why People Become Overweight. Retrieved from

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