Metabolic Rates

How many Calories do you burn in a day? How many Calories should you be consuming to lose, maintain, or gain weight? The first step to answering these questions is to determine your metabolic rate.

Your basal metabolic rate (BMR) is the amount of calories you burn in a day just by doing autonomic bodily functions like breathing, heart beating, hair growing, and maintaining temperature. This is based largely on your size and age. You can use calculators, like this one, to estimate your BMR. Please note that these are only estimations. Your true BMR is going to be affected largely on muscle mass. The more muscle you have the more Calories you burn to maintain that mass. Also, your hormone levels also affect your BMR.

After determining your BMR, you need to calculate how many calories you burn doing your basic daily activity (this does not include exercise). This is called you active metabolic rate. This considers the type of work you do during the day. Think of it as a scale of 1-4.
1-sedentary (mostly sitting: receptionist, accountant)
2-little active (standing and walking)
3-more active (moving quickly, some lifting)
4-very active (construction worker)
I consider myself at a 2 so I would multiply my BMR by 1.2 to determine the amount of Calories I use in a day minus my workout. A construction worker would multiply his/her BMR by 1.4.

If you are trying to lose weight, you need to create a Calorie deficit meaning you must burn more Calories than you consume. In that case, eat less than the amount of Calories you calculated. If you are very overweight it is safe to create a larger Calorie deficit. If you need to lose 20 lbs or less, you should have a smaller Calorie deficit. That being said, you should never let your Caloric intake be less than 1100 Calories for women or less than 1400 for men. Doing so is going to put your body in starvation mode. This makes your body catabolic (break-down muscle, stores fat) instead of anabolic (build muscle, burn fat). Yes, you will lose weight, but much of that weight will be muscle and when you start eating normal, you will gain all the weight back because of the catabolic state your body is in: yo-yo dieting is established. Starvation can cause serious damage to your metabolism.

Of course, you can also create a Calorie deficit by exercising more. One problem with doing this is that exercise requires energy and the more you exercise the hungrier you become. Plus, working out for 30 minutes a day will only burn about 300 Calories, not enough to create a significant deficit especially if you are not tracking the amount of Calories you consume. That being said, try to eat less than the active metabolic rate that we calculated above if you want to consistently lose weight. If you had a serious workout and are starving, don't be afraid to eat a little. Just don't eat back all your Calories and waste all the hard work you have done.

If you are trying to maintain weight, eat as many Calories as you use in a day and take in consideration how much you exercise. A good way to calculate the number of Calories you burn in an exercise is to assume you are burning 10 Calories per minute which is a pretty standard average.

If you are trying to gain weight, increase your Calories consumed by eating more lean protein and incorporate strength training into your workout.

None of this will matter if you are completely unaware of the amount of calories you consume. Weight loss is basic math based on this equation:
Calories consumed-Calories burned
In order to lose weight, you must have a Calorie deficit. It is as simple as that. So make sure you are aware of the amount of Calorie you consume. Most people assume they eat less Calories than they actually do. Take a notebook and for at least a week, track the amount of Calories you eat. It really isn't very hard. Look at nutrition labels and take into consideration the serving size they list. If one bowl of cereal is 140 Calories for 1 cup and you eat 1.5 cup, write that you have consumed 210 Calories and remember to look at the milk. Don't be afraid to use a measuring cup to be completely accurate. There are also many websites, like this one, that list the Calorie content of food, even fast food. I was horrified that my "healthy" choice of a grilled chicken jalapeno sandwich at Carl's Jr was 670 Calories. That in itself is a good reason to stay away from fast food.

You will find it is pretty difficult to stay under your Calorie goal. If you have a bad day, don't give up. Just exercise more that day. You can allow yourself some treats, but that leaves you less Calories for the rest of day.

So here is the challenge: Track you Calories for at least a week and try to stay under you Calorie goal.