Weight Loss Basics Explained

I covered the nitty gritty of digestion from a biological point of view in yesterday’s post. But say you just want to lose that paunch you’ve developed from too many late-night viewings of Dr. Who (accompanied by salty buttered popcorn). Let’s find out:

Say I’ve got a friend, Rose Tyler. Rose is 5’9”, weighs 180 lbs (slightly overweight), consumes 2000 Calories daily, and exerts herself enough to not gain or lose weight. She wants to lose 10% of her bodyweight for a final (and healthy) weight of 162 lbs. A healthy rate of loss is 1-2 lbs/week, so this could take 9-18 weeks to achieve.

1 pound [2.2kg] of body fat is the same as about 3500 Calories [kcal]. Thus to burn one pound of fat requires an expenditure or deficiency of 3500 Calories. Since we’re shooting for 1-2 lbs weekly, that means:

(3500 Calories/week)*(1 week/7 days) = 500 Calories less (or extra exercise) daily. Double this (1000 Calories) for 2 lbs/week.

Reducing food intake is tricky. Undernourishment is possible—especially when exercising—and also puts you at risk of going into “survival mode”, when your body stores more calories as fat. I’d tell Rose to eat a small snack before and after her work out, which should also last a bit longer to account for the extra calories. Eating before and after is helpful in maintaining muscle mass, and also ensuring enough fuel to burn and recover. Also, eating several smaller meals throughout the day evens out caloric intake and ensures your body always has the energy it needs. There are other ways to do this, but you’ll have to wait for the next post!