Weight gain is not just a fluke; it is a symptom of Western diet and lifestyle—our thoughts and actions being out of balance with our genetics and evolution. As incredible as this may sound, the ability to modify behaviour of your genes to influence weight loss is a key concept in this book. Epigenetics is the scientific field that looks at how genes interact with our diet, environment, lifestyle and even emotions, to change the expression of our genes for better or worse—and in the case of weight gain, for worse.

In a very real sense, everything that happens in our bodies ultimately takes place on a genetic level. Nothing happens without the genes being involved, either directly or indirectly. And the way our genes are programmed is largely a product of our environment and our evolution. A large body of research clearly shows that good health, abundant energy and weight management all rely on the normal functioning of genes which, in turn, depends on a healthy environment, diet and lifestyle. The research also shows that you can improve your weight and health, regardless of the genes with which you are born. You are not stuck with genes that make you gain weight.

Many of today’s health problems result from what amounts to a collision between ancient genetics and modern, highly processed foods. Our genes are routinely exposed to genetically unfamiliar foods and chemicals, and they respond abnormally, such as by triggering inflammation, chronic illness, low energy and weight gain. We evolved in a rich environment full of nutrient-dense foods and only the stress of the hunt—a very different scenario than our lives today. In times past, every calorie consumed came with large amounts of vitamins, minerals, proteins and healthy fats, relatively little starch and almost no grain. Many ancient diets were extraordinarily diverse, including up to a hundred different types of plant foods, as well as scores of land animals, many species of fish and wild bird eggs.

Today, we are living out of balance, and paying the price. It doesn’t take much to put on extra weight. Even small disturbances in energy balance may lead to the onset of obesity.