Wednesday, February 27, 2008

Losing Body Fat and Calorie Deficits

Creating a 'Calorie deficit' is the critical step to lose body fat. A Calorie deficit (capital 'C' when we are talking about food energy, which is actually a kilocalorie, 1000 calories. The picture is of a calorimeter, as used in the chemistry lab.) is the difference between the energy you use and the energy you take in (Calories burned - Calories eaten). That difference will come from stored energy in your body. Now, most of the time that is body fat, but when the deficit is large or there are other stressors it can include muscle, water, and glycogen (stored carbohydrates in the muscle and liver).

So, how do we lose body fat and not muscle? The key is the size of the Calorie deficit. Creating a small Calorie deficit, about 100-300 Cal/day is probably ideal. However, since a pound of muscle contains approximately 3500 Calories, you will be losing a pound of fat in 12-35 days! But, the trade-off is that you will keep or build muscle, have plenty of energy and nutrients, and not feel like you are starving yourself. When someone has a lot of bodyfat (>50lbs) to lose the Calorie deficit could be higher.

How do we create this calorie deficit? Increasing the expenditure part of the equation and decreasing the intake is the answer. 'Diets' (a four-letter word...need I say more) are a drastic decrease in your Caloric intake, usually with out much increase in Calorie expenditure (in fact, dieting causes a decrease in expenditure because your resting metabolic rate slows and you don't feel as energetic to do much physical activity). I recommend a small decrease in Caloric intake (100 of your 300 Cal/day), and a larger increase in expenditure with regular exercise (yes, it has to be regular). Aerobic and resistance exercise can help you create the remainder (200 of your 300 Cal/day). My training programs utilize the best exercises (using the most of your muscle mass with good intensity) to help you burn many calories during the session and elevate your resting metabolism up to 48 hours afterwards.

Hopefully, everyone knows that the scale doesn't accurately show a lose of body fat. Body composition analysis is the best indicator of change in your body fat and muscle mass.

It now should be apparent that healthfully losing body fat and keeping it off is a long-term endeavor that includes regular exercise and maintaining a small net Calorie deficit.

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