Expert: Todd Bublitz, RCEP - 1/4/2007

Question
I weigh 169 and Im 5'5. I need to get down to about 145-150 which isn't too bad. But I was wondering how many calories a day I can eat and lose 3-5 pounds a week. I want to be healthy while I do it too. I've been swimming an hour about three nights a week. I'd like to move that up to five with 30 minutes of exercise before, not including the crunches and set ups I do everyday anyways. It this a healthy way to go about it.

Answer
Whitney,

Your current exercise routine of swimming and crunches sounds good. I'd avoid "sit ups" of you already do crunches, since sit ups are much more likely to lead to injury.  Increasing your exercising to 5 days a week is also a very good idea, as long as you are generally healthy.  It's always a good idea to have your doctor give you a check up and get "approval" from your doctor prior to starting any exercise routine.

HOWEVER.....

Trying to lose 3-5 pounds a week is completely unrealistic.  
Here is why:
You need to burn 3500 calories, or not eat 3500 calories (or a combination of eating less and exercising more), to lose one pound.  If you multiply 3500 times 4 pounds, you get 14,000 calories, that you need to "lose" each week to lose 4 pounds a week.

Swimming for an hour burns about 400-500 calories.  If you swim 5 hours a week, you will burn 2250 calories a week.  If you add 30 minutes of exercise to your routine, you may burn another 500-1000 calories a week. [Cardiovascular / aerobic exercises burn more calories than resistance / weight lifting.]  Let's say that you are burning about 3000 calories a week through exercise.  You now need to eat 11,000 calories LESS each week and this amounts to eating 1500 calories LESS EACH DAY.  And this is totally unrealistic.  You are probably eating about 2300-2500 calories a day now, give or take a couple hundred calories.  You need to eat at least 1500 to 1800 calories each day to get enough nutrients and calories to keep you going.  If you eat fewer, you won't have enough energy to do your exercises.

Many studies have shown that the more slowly you lose weight, the more likely you will keep it off.  The golden amount seems to be 1-2 pounds a week maximum.  If you burn about 3000 calories a week exercising and eat 300-500 calories less each day, you will lose 1.5 to 2 pounds a week.  This is much more realistic.

I hope this helps.

Todd