Calories and Your Health

First off, what is a Calorie? 
Ask one hundred people what a calorie is and most will tell you it is "the thing in food that makes me fat." Calories have gotten a bad reputation and are considered by many to be the enemy.

Few people truly understand what a calorie is and why it is so important to their bodies.  By definition a calorie is the energy it takes to raise the temperature of 1 gram of water 1 degree Celsius.

The number of calories in a food is a measure of how much potential energy that food possesses. A gram of carbohydrates has 4 calories, a gram of protein has 4 calories, and a gram of fat has 9 calories. Foods are a compilation of these three building blocks. So if you know how many carbohydrates, fats and proteins are in any given food, you know how many calories, or how much energy, that food contains.

The important word to take away from this definition is ENERGY

Calories are ENERGY that fuel our bodies; much like gasoline fuels our cars. Without sufficient calories our heart would not beat, our lungs would not function, and our brain would not work. Many of us have no idea how many calories our body needs just to exist.

How many calories should you eat?
Just how many calories do our cells need to function well? The number is different for every person. You may notice on the nutritional labels of the foods you buy that the "percent daily values" are based on a 2,000 calorie diet -- 2,000 calories is a rough average of what a person needs to eat in a day, but your body might need more or less than 2,000 calories. Height, weight, gender, age and activity level all affect your caloric needs. There are three main factors involved in calculating how many calories your body needs per day:

• Basal metabolic rate
• Physical activity
• Thermic effect of food

Your basal metabolic rate (BMR) is the amount of energy your body needs to function at rest. This accounts for about 60 to 70 percent of calories burned in a day and includes the energy required to keep the heart beating, the lungs breathing, the kidneys functioning and the body temperature stabilized. In general, men have a higher BMR than women. One of the most accurate methods of estimating your basal metabolic rate is the Harris-Benedict formula:

• Adult male: 66 + (6.3 x body weight in lbs.) + (12.9 x height in inches) - (6.8 x age in years)
• Adult female: 655 + (4.3 x weight in lbs.) + (4.7 x height in inches) - (4.7 x age in years)

The thermic effect of food or TEF is the energy expended by our bodies in order to consume (bite, chew and swallow) and process (digest, transport, metabolize and store) food. We "expend energy" by burning calories.

Processing protein requires the greatest expenditure of energy, with estimates ranging as high as 30%. Dietary Fat, on the other hand, is so easily processed and turned into body fat that there is little thermic effect, perhaps only 2 or 3%. The amount of energy required to process carbohydrates falls between that of protein and fat.

Weight gain and loss
If you exceed the number of calories your body requires each day you will eventually gain weight. It takes an excess of 3500 calories to gain 1 lb. of fat. For example, if your body needs 2000 calories a day to maintain its current weight and every day you consume 2500 (one 20 oz Latte could add 500 calories) in one week you would gain 1 lb. One day of overindulging does not cause instant weight gain.

To lose weight you need to use/burn more calories then you consume. Example: If you eat 2000 calories a day, and are maintaining your weight, you would need to burn 250 calories (30 minutes high impact aerobics for a 150 lb. person) per day to lose a 1/2 lb in one week. If, in addition, you decreased your caloric intake by 250 calories a day (a 20oz soda), a 500 calorie a day total deficit, you could then lose 1 lb per week.


Video Link --> Calorie Density

So what is Calorie Density?
Foods that are high in water and low in fat -- such as fruits, vegetables, soup, lean meat, and low-fat dairy products -- are low in calorie density and provide few calories per bite. "Eating a diet that is low in calorie density allows people to eat satisfying portions of food, and this may decrease feelings of hunger and deprivation while reducing calories"

Penn State researchers completed a year-long clinical trial to show that diets focusing on foods that are low in calorie density can promote healthy weight loss while helping people to control hunger.  The Penn State researchers added that increasing the consumption of water-rich foods such as fruits and vegetables is not only in tune with current dietary guidelines, but may also help reduce the risk of chronic illnesses.

To read the entire article about this study: http://www.sciencedaily.com/releases/2007/06/070608093819.htm

Ok, so what does all this mean?
It boils down to this; we all need calories but everyone's caloric needs are different.  People that are active and healthy generally require more calories than people that are sedentary and unhealthy. 

The types of calories you consume are very important.  A healthy diet involves much more than just counting calories.  In fact, if all you do is count calories you are missing the important part of nutrition which is what you eat.  People that eat foods that are less calorie dense can eat many more calories without worrying about weight gain or its associated health risks.  That's because whole foods such as fruits and vegetables and lean proteins are not causing the obesity epidemic world wide. 

It's not a bad idea to know how many calories you consume but it is not as important as knowing what is in the foods that you are consuming.  Eat better food and stop worrying. 

Be well.