CALORIES: All metabolic functions in our body require energy in order to happen, just as an automobile requires energy to go. In a car, gasoline is burned to produce this energy. In our body, food is “burned, in a sense, to produce this energy; that is, we metabolize our food to give the body the energy it needs to function.
When we give our body more fuel than it needs, this excess is stored as fat for future use. In the days when our next meal depended on the next saber toothed tiger coming by, this was fine, as the stored energy may well be needed. However, most of us get our fuel today not from a saber tooth but from the supermarket and the ‘fridge, so any excess fuel that is stored is not likely to be for future use, so body fat accumulates.
The balance of calories consumed in the form of food compared to the calories we expend (“burn”) determines our energy or calorie balance. There are only three possibilities here:
- We consume more calories than we burn. Here, the excess calories would be stored as body fat.
- We consume fewer calories than we burn. Here, the additional calories needed are obtained by braking down body fat.
- We consume the same number of calories we burn. Here, no body fat is stored, none is broken down. Body weight is maintained.
There are three ways in which calories are burned:
- Metabolic function: This refers to the bodily functions necessary to sustain life and keep our bodies working, such as the pumping of our hearts, the breathing of our lungs, and all other organ and cellular functions.
- Physical Activity: This has two components:
- Activities of daily living: These are the things we do as we go through our day, such as walking to the car, walking to the office, shopping at Whole Foods, and checking the mail.
- Exercise: Exercise is any dedicated activity whose purpose is to burn calories and improve emotional, spiritual, and physical health.
How is my metabolism determined?
The number of calories consumed by metabolic function is determined by:
- Age: The older we become, the fewer calories we burn, as metabolic function slows.
- Gender: Females have a comparatively slower metabolic rate than males.
- Body weight: The more you weigh, the more you burn in metabolic function.
- Height: The taller you are, the more you burn.
- Body Composition: This refers to the amount of your body which is composed of fat as compared to lean body weight such as muscle, bone, etc. Those with less body fat and more muscle will burn more calories in metabolic function, as muscle is a metabolically more active tissue than fat.
- There are several formulas that can be used to compute the number of calories we burn each day, depending on how precise we want to be. The greatest source of calorie expenditure is our metabolic function, or BMR, Basal Metabolic Rate. This can be estimated with the following formula:
|BMR for women =||665 +||(9.6 x Weight) +||(1.7 x Height x 2.54)||–||(4.7 x Age)|
|BMR for men =||66 +||(13.7 x Weight) +||(5 x Height x 2.54)||–||(6.8 x Age)|
|(weight is in pounds, height is in inches)|
This formula is an approximation, as it does not take into account the effect our body fat composition has on out metabolic rate. A more precise measure of our metabolic rate can be obtained by determining our percent body fat, which we can do for you at Nature’s Healthcare.
WHAT CONTROL DO WE HAVE OVER THE NUMBER OF CALORIES WE BURN?
We can’t change our height or our age. We can change our weight, but at a stable weight, the only impact we can have on our metabolism would be in our percent body fat. As we replace body fat, by losing it, with muscle, by adding it, out metabolic rate will go up.
- ACTIVITIES OF DAILY LIVING: We can increase the number of calories we burn as we go through our day by changing HOW we go through our day, and studies have shown that people who address these daily activities are better able to control their weight. For example, we can burn more calories walking to the car if we parked our car farther from the office or the store. Likewise, we will burn more calories taking stairs instead of elevators.
- EXERCISE: We obviously have control over this. We burn zero calories for no exercise, 100-200 for a moderate walk, 450 for an hour of tennis, and 950 for eighteen holes of golf carrying your bag. This can be whatever you make it, and tables are available with calories burned with different types of exercise.
WHY DO I NEED TO KNOW THE NUMBER OF CALORIES I BURN?
Once you know how many calories you burn, you can then target a specific number of calories to consume, so as to be in control of whether you lose weight or maintain your current weight. And, once you know which factors you can control, you can implement the appropriate lifestyle changes to address them.
Research in weight management programs shows that control of dietary fat is more important than dietary sugar with regards to weight loss and weight maintenance. As well, limiting the intake of dietary fat has also been shown to reduce the risk of developing heart disease, stroke, and cancer.
Please refer to our handout on dietary fat for more details regarding fat metabolism and so forth. In this handout we are giving you the sound bites regarding dietary fat as well as some numbers you can take to the bank.
- First and foremost, the less fat the better.
- Calories from dietary fat should be limited to 30% of total calories.
- Calories from saturated fat should be limited to 10% of total calories.
- Polyunsaturated and monounsaturated fat should be chosen over sat. fat.
- Minimize the consumption of fat from animal sources.
- Limit meat consumption to 4-6 ounces per day from fish, skinless poultry,
and lean beef.
- Limit cholesterol consumption to 300 mg per day.
- Minimize the consumption of “trans” fat (see our handout).
- Follow the Food Guide Pyramid.
- Read Labels.
The number of total calories and the number of calories from fat are really all you need to know with regards to weight management. However, another way of keeping track of fat consumption is to count the number of fat grams consumed. Targeting this number can help you keep your fat intake under the 30% ceiling.
To determine the maximum number of fat grams per day:
- Determine your daily calorie expenditure as above.
- Multiply that number by 30% (.30).
- Fat has 9 calories per gram; so divide the number in number two by 9 to get the number of fat grams per day to keep fat calories to 30%.
Example: If your calorie expenditure is 2200 calories per day, the number of fat grams would be:
- 2200 x .30 = 660 cals per day from fat
- (660/9) = 73 grams of fat per day
Every 600 total calories computes to 20 grams of fat. So:
- for 1000 cals pet day, limit fat to 33 grams per day
- for 1600 cals per day, limit fat to 53 grams per day
- for 2800 cals per day, limit fat to 93 grams per day
We hope you find this information helpful in your effort to improve your health and wellness through these dietary and lifestyle changes. The staff at Nature’s Healthcare is available to help you with any questions you may have about implementing these changes.