Your genes are not only involved with your physical appearance but also involved in daily interactions that effect your health and your weight. Scientists are now beginning to understand how genes play part in the direct effect on health and weight loss. The metabolism, storage and absorption of macronutrients (calories, fats carbohydrates and proteins) are directed by your genes. This may explain why, you and a friend may follow the same diet but you do not lose the same amount of weight. Various genes have different working mechanisms. These interactions are affected by the environment and yes that includes the food you eat.
How can body weight be affected by genes? Just a few ways are featured at, http://www.weight-loss-i.com/body-weight-genes.htm, and they list: appetite, fat storage, Basal Metabolic Rate (BMR) and lean body mass to fat ratio.
Genes and related Factors on Weight and Blood Sugar (Diabetes):
These are just a few examples of contributing factors effecting excess weight and diabetes beyond the calorie hypothesis.
- Ob(Lep) gene: Jeffrey Friedman, a Hughes researcher at The Rockefeller University in New York, linked both obesity and diabetes to the Ob(Lep) gene. Obesity was associated with a lack of this gene contributing to a lack of leptin and therefore a lack of satiety. Diabetes was linked with a lack of the gene that creates the leptin receptor (a receptor is a molecule with the ability to bind with leptin), http://www.hhmi.org/genesweshare/d130.html.
- CB1, is a receptor involved in cannabinoid (pronounced: can∙ na∙ bin∙ oid) receptor activity, http://www.news-medical.net/health/Cannabinoids-What-are-Cannabinoids.aspx, and seems to be involved with the development of insulin resistance, http://www.sciencedirect.com/science/article/pii/S0016508512001527.
- TCF7L2: The research on this gene is interesting in that when obese individuals had 2 copies of the transcription factor 7-TCF7L2 they responded more positively to a low fat diet, and yet those who were TCF7L2 rs7903146 carriers(or had only 1 copy of transcription factor 7-TCF7L2) were at higher risk for type 2 diabetes when higher amounts of carbohydrates were consumed,http://xa.yimg.com/kq/groups/16623456/1581108334/name/Wylie-Rosett%20et%20al%20Curr%20Diabetes%20Report%202012.pdf.
- FGF21 is a hormone secreted by the liver during fasting that helps the body adapt to starvation and seems to have a dual role of increasing insulin sensitivity (to help ward of blood sugar, diabetes, heart disease, cancer and any health related insulin issue) and diabetes and protective against metabolic hormone predominantly produced by the liver. FGF21 seems to provide its health benefits by increasing insulin sensitivity and preventing the release of insulin-like growth factor-1 (associated with insulin resistance, cancer), http://www.sciencedaily.com/releases/2012/10/121016103411.htm
Nutrigenomics (the study of the effects of foods on genetic behavior) is a new field that is likely going to prove how much we DO NOT know about nutrition and current dietary recommendations.
If the diet you are now following does not work, it may simply be because you and your body are not in sync, you have not found the diet that your body is looking for. You may need to explore subtle variations in your current eating regimen. You may need to work with an experienced weight loss expert who can assist you in your weight loss and improved health journey. There is hope, keep trying.
It may not be your fault that you are trying to lose weight and are not successful.
What is important to realize is that individualized diets based on genetics, will be more available in the future.