Do the Genes Fit?

These genes do not refer to a favourite pair of pants, but to the human genetic make-up. Is it possible that our genes are responsible for the obesity epidemic? When first looking at the research, it might seem that way, but in fact, genes are only part of the answer.

Rewind to a few thousand years ago. Imagine being a hunter-gatherer living in a world where food is scarce and physical activity is plentiful. Since no one knows when the next meal will be, it is important to store extra energy when food is available. Fast-forward to the present day. Our genetic make-up is almost the same as the hunter-gatherers, however our modern lifestyle has changed dramatically.

Today we live in a sedentary society and are surrounded by food. It is common for a person to spend much of the day driving, working at a desk, or watching television. It has also become easy to choose low-cost, high fat and high sugar foods for snacks and meals. This type of lifestyle may promote overeating. Excess energy the body does not need will be stored as fat.

Although we share almost 99% of our genetic make-up, there are small differences between us. The risk of developing obesity is affected by how these genetic differences interact with lifestyles and the environment. This explains why some people making similar lifestyle choices may gain or lose weight more easily than others. Also, people who share their genetic make up will be affected by obesity in a similar way. This includes people such as twins or parents and children.

The complex link between genes, lifestyle, and obesity can make it seem difficult to be healthy. Luckily, there are many choices we can make to improve our health. Eat more vegetables. They are low in calories, taste good and help us feel full. Take a walk during a break at work or school. Moving around can:

  • § Help strengthen muscles and bone.
  • § Improve mood and mental health.
  • § Reduce the risk of developing many chronic diseases. Are genes responsible for the obesity epidemic? Only partially. The obesity epidemic is the result of a complex link between genes and lifestyle. We will need to work together if society is to successfully tackle this epidemic.


Originator: Calysta Adams (Dietetic Intern) and Victoria Jurgens RD, Prince Albert Parkland Health Region

Editing Buddy: Jennifer Miller RD


Ahmed, S., Lemkau, J., & Birt, S., “Toward Sensitive Treatment of Obese Patients”,, 2002.

Centers for Disease Control and Prevention, “CDC Features: Obesity and Genetics”,, 2008.

Centers for Disease Control and Prevention, “Physical Activity and Health,”, 2008.

Comez-Santos, C. Madrid, J., Mernandez-Morante, J., Lujan, L., Ordovas, J., & Garaulet, M., “Circadian Rhythm of Clock Genes in Human Adipose Explants – Obesity”,, 2009.

Dahlman, I., & Arner, P., “Obesity and Polymorphisms in Genes Regulating Human Adipose Tissue”, International Journal of Obesity, Vol. 31, 2007, pp. 1629-1641.

Dietitians of Canada, “Healthy Weights/Obesity: Key Practice Points: Evidence/ References”. In: Practice-Based Evidence in Nutrition [PEN],

“Do These Genes Make Me Look Fat?”, Daily Grow Magazine,, 2008.

“Expectation of Tasty Food can Trigger Brain Reward”,, 2009.

Harris, G., Wimmer, M., & Aston-Jones, G., “A Role for Lateral Hypothalamic Orexin Neurons in Reward Seeking”, Nature, No. 437, 2005, pp.556-559.

Loos, R., & Bouchard, C., “Obesity – Is it a Genetic Disorder?”, Journal of Internal Medicine, No. 254, 2004, pp.401-425.

Loos, R., & Rankinen, T., “Gene-Diet Interactions on Body Weight Changes”, Journal of the American Dietetic Association, Vol. 105, No. 5 (supplement), 2005, pp.29-34.

Lyon, H., & Hirschhorn, J., “Genetics of Common Forms of Obesity: A Brief Overview”, American Journal of Clinical Nutrition, No. 82 (supplement), 2005, pp. 215S-7S.

Merchant, A., Vatanparast, H., Barlas, S., Dehghan, M., Shah, S., de Koning, L., & Steck, S., “Carbohydrate Intake and Overweight and Obesity among Healthy Adults”, Journal of the American Dietetic Association, Vol. 109, No. 7, 2009, pp. 1165 – 1172.

Puhl, R., “Weight Bias in Healthcare: An Important Clinical Concern”,, 2009.