- While eating healthy and exercising are important for maintaining a healthy weight, so are some non-modifiable factors such as genetics.
- Researchers from the University of Essex found 14 “skinny genes” that may work together to assist with weight loss.
- Despite having these genes, scientists say that diet and other lifestyle factors are still vital for losing and maintaining a healthy weight.
“Obesity is a worldwide epidemic that is an increasing issue and burden to society, economy, and health sectors,” Henry Chung, PhD, a lecturer in Sport and Exercise Sciences at the School of Sport, Rehabilitation and Exercise Sciences (SRES) University of Essex explained to Medical News Today. “It is well established that things like exercise and diet are known factors to combat obesity.”
“However, it is not that simple, and there are multiple factors that cause obesity and excess weight gain. More importantly, there always seem to be variations in how much weight people can lose even when doing the exact same exercise. Therefore, we look to genetics to explain these differences and how this can be used to shape future interventions,” Chung continued.
For this study, researchers recruited 38 adult participants between the ages of 20 and 40. Study participants were randomly assigned to either an exercise training group — which used a running program — or control group for eight weeks.
Both groups were told not to change their usual diets and not to do any additional exercise.
At the end of the study, all participants were screened for 1,000 gene variants, which helped them identify a combination of 14 genes that may improve weight loss.
“In simple terms, all the genes identified in our study are common ‘health and fitness related genes’, and previous research has identified the role of each gene separately and what it does. In basic terms, the genes in this study, in some roundabout way, are related to energy balance and the metabolic pathways that use fuels in the body. What is interesting is that these genes have been assessed separately but our study showed they all contributed/interacted together to affect weight loss,” Chung explained.
“We looked at 1,000 genes in total, so it is even more interesting that these specific ones that have been shown to be related to exercise, popped up. Theoretically it makes sense why they would contribute to weight loss. They are related to how the body uses energy and metabolizes our food to produce energy. They are involved in key systems like fat metabolism, so someone with these ‘advantageous genes’ might have a better fat-burning system/ability during exercise compared to someone that doesn’t have the same genes.”
— Henry Chung, PhD
At the study’s conclusion, researchers found that participants in the exercise group who had the most “skinny genes” lost up to 5 kg (about 11 lbs) during the study, while those without them dropped an average of 2 kg (about 4.4 lbs).
Scientists reported that the PARGC1A gene that encodes PGC-1-a — which plays an important role in cellular energy metabolism — seemed key to weight loss and was identified in study participants who lost the most weight.
“The PPARGC1A gene encodes for PGC-1α, which (is) a transcriptional coactivator that regulates energy metabolism and mitochondrial function. The increase in the upregulation of this means that doing something like exercise increases proteins such as increased CD36/FAT (fatty acid translocase) and FABP (fatty acid-binding proteins), facilitating the transport of fatty acids across cell membranes,” Chung detailed.
“Once it gets to the mitochondria, PGC-1α enhances the expression of enzymes like acyl-CoA dehydrogenase, which is essential for the initial step of fatty acid β-oxidation, where long-chain fatty acids are progressively broken down into acetyl-CoA which is essential for (the krebs) cycle.”
“In short if you have this gene and someone does not, it could be speculated that you will one, have more energy than them, and two, be able to burn more fat into working energy rather than storing it — this gene is roughly in 20-40% of the world population,” he added. “In the past it has been related to mitochondrial biogenesis, gluconeogenesis, energy metabolism (including lipid metabolism), cholesterol homeostasis, and therefore obesity.”
Chung and his team stressed that while having “skinny genes” may assist with the weight loss process, that does not mean to forgo exercising and eating healthy.
“The bottom line is that for the majority of people if you do not do any exercise at all, the genes you have might not matter. If you do not do something with them, their genetic potential will never flourish — only when we add stress the body systems respond, and then the body adapts.”
— Henry Chung, PhD
“It is all about knowing the best interventions that work well for you and when to apply them, which is a large part of the battle,” he added.
Chung said the main takeaway from this study was that there were no one-size-fits-all approaches and people need personalized training strategies.
The study does have some limitations. The authors note that the genotype DNA chip they used only has 1,000 single nucleotide polymorphisms, whereas other chips have thousands.
“It is likely, therefore, that interactions may have been omitted,” they said. More research is needed into these possible interactions as well as into the link between genetics, diet, and obesity.
MNT also spoke with Mir Ali, MD, a board certified bariatric surgeon and medical director of MemorialCare Surgical Weight Loss Center at Orange Coast Medical Center in Fountain Valley, CA, about this study.
“This is an interesting study, though with a small number of participants, that confirms what other studies have shown that genetics is a significant contributing factor to set a patient’s weight and overall body composition,” Ali said. “Obesity is a multifactorial disease, and genetics is just one component. The researchers emphasized that even people with ‘skinny genes’ still must eat the right foods and exercise.”
“Having a genetic predisposition to either skinny or overweight does not mean that this cannot be overcome. Even if someone is not overweight, and they eat the wrong foods, they can still develop significant health issues. A healthy diet and exercise are important for everyone to maintain a healthy weight and avoid health issues. Unfortunately, no one diet or exercise regimen is perfect for everyone, and the difficult part is to determine what works best for each individual.”
— Mir Ali, MD
“Extending this research to include the optimal diet for different genetic types would be useful to help patients determine what is best for them to achieve and maintain good health,” Ali added.
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