Weight loss is a billion-dollar industry. The growing North American epidemic of obesity combined with recent social trends towards healthier lifestyles has made weight loss a highly sought-after goal. With all the misconceptions and poor products out there, I’d like to take the time to explain where science stands on the question of body weight.
 
Weight management is actually a very simple concept, scientifically. Your body is very efficient at converting food energy into body mass in the form of muscle, bone, fat and other tissues. When there is a surplus of food energy, the body stores it just in case a period of starvation is coming. The main storage form of this surplus energy is fat. When there isn’t enough food energy to support the body’s activities, then the body gets as much as it can from the food, and generates the rest of its energy from body stores (mostly fat). The bottom line of this system is that if weight loss is desired, then one needs only use more energy in a day than one is taking in.
 
There are three numbers that affect a person’s energy balance – basal metabolic rate (BMR), energy expenditure (EE) and energy intake (EI). The BMR is how much energy it takes to keep your body running during the day if you’re not doing anything – this number is unique to each individual, and somewhat difficult to change. The energy expenditure (EE) is the amount of energy you use to move around and do all the things you do in a day (including exercise). The energy intake (EI) is the amount you’re eating in a day. If your BMR + your EE is greater than your EI, you will lose weight. It’s as simple as that. All weight loss works on the concept of altering these numbers. Currently, the majority of generic weight loss products act as laxatives, thereby decreasing the amount of food energy absorbed in the intestines. Although this does decrease EI, it is a messy, uncomfortable and generally unhealthy way of losing weight. Others products can change a person’s BMR slightly, but this is dangerous and can cause many health problems.
 
This is not to say that all products are bad. PGX for example decreases EI by decreasing a person’s appetite, thereby avoiding the harm caused by laxatives. Healthy, scientific, effective weight loss requires modest restriction of calories to decrease EI (don’t starve yourself) combined with regular medium-intensity exercise to increase EE (no need to work out until you fall over). Starting from a diet in which you are neither gaining nor losing weight, if you keep to a reduction in calories of about 500 cal/day and engage in about 500 cal/day of exercise you’ll see a healthy, scientific weight loss of about 1-2 lbs a week. Stick with it and you’ll reach your goals.