Weight gain and stress
Emotional eating means eating for comfort. It makes us feel better, but it doesn’t last, and so we overeat and might gain the extra weight.
The MC4R gene is well-known for its role in the regulation of energy balance. It is also widely expressed in stress-regulatory brain regions. This double role makes that gene a link between our metabolism and our habits of eating as an emotional response.
When under emotional stress, people carrying an MC4 variant not only overeat, they also conserve more of the excess energy and gain more weight than others.
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Gene: MELANOCORTIN 4 RECEPTOR; MC4R
Genomic coordinates (GRCh38): 18:60,371,330-60,372,767
MC4R is well-known for its role in the regulation of energy balance. In addition, it is widely expressed in stress-regulatory brain regions. MC4R actually serves as an important link between brain metabolic and stress systems.
Carriers of the MC4R minor alleles tend to be more obese, with higher intakes of processed foods and fat.
Although a direct link is found between the variant and higher BMI, the majority of the effect is through emotional eating:
Recent findings show that subjects with the specific MC4R variant have a low metabolic tolerance for excessive energy intake, especially when under stress. In other words, much of the weight gain is due to a stronger tendency of carriers to accumulate the extra calories as fat. Non-carriers eat less junk, and metabolically get rid of some of the extra calories. Carriers however, when under stress, not only eat more but also conserve the extra calories better.
To sum it up, scientists found that the MC4R effect is specifically strong under stress conditions. Under high stress levels, people carrying this variant would gain much more weight than other people.
There is another functional variant in the MC4R, which causes the opposite effect on metabolism. A large meta-analysis study, covering more then 55,000 individuals from different ethnic backgrounds, has confirmed that about 3% of the general population carry a rare variant that grants a protective effect against obesity. This protective effect is significantly greater than the common form of the first variant we talked about, leading to a greater reduction in chances for being obese. GeneInformed is testing for this one as well, so don’t worry, we will tell if you are one of the few lucky ones.