The Science of Weight Loss


At a physiological level, weight loss and weight gain revolve around caloric consumption and expenditure. Because of this, it's important to understand the basics of calories. Put simply: we lose weight when we eat less calories than we expend. Conversely, we gain weight when we eat more calories than we expend. In order to lose one pound of fat, we must create a 3,500 calorie deficit, which can be achieved either through exercise or diet.

DIETING AND MECHANISMS OF WEIGHT LOSS

3 Groups – One Consistent Finding

  • 95% of all dieters regain their lost weight within one to five years

  • Several long-term follow-up studies have shown that the success rate of diets, over time, is dismal at best. It is estimated that 95% of diets simply don’t work over the long term

  • Studies have shown that 90-95% of individuals who diet are unsuccessful in the long term

Why don’t diets work?

  • They focus on short term results (vs long term, permanent weight loss)

  • They focus on reducing calories as the priority (often at the expense of good nutritional principles)

  • They often change the ratio of fat to muscle mass negatively (which leads to further weight gain)

Mechanism of weight loss

  • Quite simply, to lose weight a person needs to consume less calories than they use OR use more calories than they consume

  • Diet programs focus on reducing calories consumed

  • Exercise programs focus on increasing calories used

  • Diet and exercise combined will obviously provide the quickest weight loss results

Metabolism and Metabolic rate

  • Metabolism

  • The chemical processes occurring within a living cell or organism that are necessary for the maintenance of life

  • Metabolic Rate

  • The rate at which your body burns calories performing normal everyday activities (neither gaining weight nor losing weight)

TDEE and BMR

  • Total Daily Energy Expenditure (TDEE)

  • 70% calories required for BMR

  • 15% calories required for exercise

  • 15% calories required for food digestion

  • Basal Metabolic rate (BMR)

  • Minimum calorific requirement needed to sustain life in a resting individual

  • BMR responsible for approximately 70% of all calories burned in a single day

BMR and Calories

The effects of exercise on BMR

Resistance training and BMR

  • Resting lean muscle mass accounts for 80% of BMR

  • Therefore increasing a person’s lean muscle mass (through high intensity resistance training) would increase their BMR