How do my genes affect my weight and metabolism?
The answer: some . . . but, probably less than you would guess!
The term "obesity gene" most commonly refers to variants within the “fat mass and obesity-associated” gene (FTO) that are associated with an increased risk of obesity. In European populations, where this association was first identified, about 45% to 65% of people carry at least one copy of the risk-associated variant. However, the increase in risk associated with the FTO gene variant is modest. Even if someone has two copies of the risk variant (one from each parent), on average they will weigh only 6.5 lbs more than those without a risk variant. The risk-associated FTO variants are generally less common in African, Asian, and other populations, but they do still occur.
The exact mechanism by which genetic variants such as FTO contribute to obesity is not fully understood. Research suggests that specific variants in the FTO gene influence appetite and how different fuels like carbohydrates and fats are metabolized. Some studies have shown that individuals with certain FTO variants may have a stronger response to high-calorie foods and may even feel hungrier shortly after eating certain foods. Apart from FTO, many other genes have been associated with obesity or body weight regulation. Examples include genes like MC4R, which plays a role in appetite regulation.
The principle task these genes perform, along with the other genes that affect how you process carbohydrates and fats, is direct whether your body uses certain energy sources now or stores that energy for later as fat. These genes also influence whether specific foods satisfy you or make you hungrier, as well as whether they raise your blood sugar or cholesterol.
When we work with patients at Rise Precision Medicine, we analyze their genetics and prescribe a two week continuous glucose monitor to scrutinize how they metabolize different foods. Patients are genuinely amazed when they utilize precision nutrition, because they feel so much better, their appetite is satisfied, and their physical performance improves. You would think a person who is eating a low carb diet would have well controlled blood sugars, right? Not for people with certain genetic variants. Recently, one of our patients was on a low carb diet and his blood sugars were running in the prediabetic range. He also was struggling to improve his running speed for 5k and 10k runs. We found that his diet was not at all suited to his genetics. We increased his nutrient dense, complex carbohydrate intake. His blood sugars went down significantly, as did his 10k running time! Our patients often find that hunger, metabolic problems, fatigue, cholesterol problems, and inflammation improve dramatically when placed on a diet that is aligned with their genetics.
It is essential to recognize that while genetics can predispose individuals to problems with their weight and metabolism, environmental and lifestyle factors such as diet, physical activity, sleep, and stress play larger roles in our weight and metabolism than genetic variations do. There is a fascinating relationship between genetics and an individual’s optimal diet. When a patient is on a diet that has been optimized to their genetics, micronutrient requirements, tastes, and lifestyle, they don’t feel hungry and they just feel and function better every day. Often, they start to lose weight because their body’s needs are satisfied by what they are providing!
