Wednesday, January 7, 2009

The All-Important Calorie Deficit

The body efficiently stores energy in the form of body fat and in order to see a decrease in body fat you need to create a long-term energy or Calorie deficit. This is simply using more energy than you take in over time. Simple thermodynamics. It is not a matter of shifting into 'fat burning' mode or out, but maintaining a net deficit over time. One of the most common fitness myths is that you need to exercise at a certain intensity (low -intensity, long duration) or do a certain type of exercise (i.e. cardio) to shift into 'fat burning mode'. This is wrong. But, it is heard frequently. In fact, you can lose a significant amount of body fat without ever performing 'cardio.'

Energy intake (fat, carbohydrate, protein, and alcohol)=
Energy expenditure
(resting metabolic rate, digestion and absorption, physical activity, exercise, and body homeostasis)

The energy intake part of the equation is pretty straight forward. It is all of the food that you put into your body. This, of course, is where dieting comes in to play. Simply cut back on the Calorie intake and you create a Calorie Deficit. This, alone, works in the short-term, but ultimately doesn't in the long-term. Decreased energy intake, ideally through portion control and proper eating habits, are still important to keep the energy intake side of the equation in check.

On the other side of equation, energy expenditure happens in a variety of ways. Most people know that increasing physical activity will result in an increase energy expenditure. However, most people don't understand how the resting metabolic rate plays an even larger role in energy expenditure. In just about everyone, unless you are Michael Phelps and train six hours a day, the resting metabolic rate is the largest component your energy expenditure. It is defined as the total amount of Calories used in 24 hours to maintain all cells in your body independent of eating or physical activity. This includes all basic cell activities like electrolyte transport, protein assembly, cell division, etc. This is on going and particularly expensive in active tissue, like skeletal muscles. In fact, there is a strong, direct relationship between total body muscle mass and resting metabolic rate. That means usually, the bigger the person, the higher the resting metabolic rate. Same is true for men versus women.

Exercise training, more specifically strength training, can elevate your resting metabolic rate, which in turn will elevate your daily energy expenditure. I will discuss this more in the next blog posting on this subject.


Julie said...

Oh, I can't believe I just signed on to read this post---I almost emailed you about this. I've been on the "Dan Hubbard Diet" (I know you will rip that apart, but it's what I call it) for three days. All it means is that I took my latest body comp and decided to actually use it--my target calories for fat loss are 1326 cal/day, and I'm shooting for the 40/30/30 of carbs, protein, fat. It's tough for me to come up to the 99g of protein, but I'm doing pretty well. However, I keep falling short in fat, and a tad high in carbs. I'm really trying to find the right balance so I'm not starving. Sage advice? Secret foods?

Dan Hubbard, M.Ed., CSCS. said...

Try to choose from a variety of meats, poultry, fish, nuts, eggs, milk, cheese, and oils to get your fat and protein. Choose from fruits, vegetables and high-protein, high-fiber (unrefined) whole grains for you carbohydrates. If you still are having problems reaching the 30/40/30 ratio, which can be tough, you may want to supplement some protein powder, flax oil, or fish oil.

Julie said...

The beginning is the hard part--trying to see what foods are most efficient, in terms of being satisfying and reaching the target %s. I'm using protein powder already--it's just a must for me to reach 100g of protein a day. Love the flax oil idea. That might be the ticket. Thanks, Dan!