The Power of Energy Balance

Energy “IN” Food provides us with the energy that we need to live. Everything we do requires some amount of energy: Running fast around a track. Sleeping. We call this energy “calories.” A “calorie” is a measure of the heat loss when food is burned.

Energy “IN” Calories in food come from: Carbohydrates (@ 4 cal/g) Protein (@ 4 cal/g) Fats (@ 9 cal/g). The food we eat contains combinations of these sources of energy.

Energy “OUT” Activities “burn” calories. Different activities burn different amounts of calories.

Energy Balance It’s important to understand the balance between the energy input (eating calories) and energy output (activities that “burn” calories) Then you can self-monitor your eating and exercise activities to stay at a healthy weight for you and decrease the possibility of disease.

Energy Balance EQUILIBRIUM Energy balance is achieved when the energy intake (food eaten) is equal to the energy output (calories “burned”). Your weight stays the same. Calorie INPUT = 2500/day Breakfast Calorie OUTPUT =2500/day Lunch EQUILIBRIUM 2500-2500 =0 Body Weight Stays the Same Dinner

Energy Balance: Equilibrium Energy In (Eating): 2000 kcal Energy Out (BMR and Physical Activity) : 2000 kcal Equilibrium: Energy Input = Energy Output 2000-2000=0 Result: Body Weight Stays the Same

Positive Energy Balance If your energy intake is greater than your energy output, then you have a positive energy balance. More calories are eaten than are burned. The result of this is that you store excess energy as body fat. Your body weight increases. Calorie INPUT = 2500/day Calorie OUTPUT =1500/day Positive Energy Balance 2500-1500 =1000 Body Weight Increases

Positive Energy Balance Energy In: 2500 kcal Energy Out: 2000 kcal Positive Energy Balance: Energy Input > Energy Output 2500-2000=500 Result: Body Weight Gain

Negative Energy Balance If your energy intake is less than your energy output, then you have a negative energy balance. Fewer calories are eaten than are burned. Your body weight decreases. Weight that is lost consists of muscle and fat tissue. Calorie INPUT = 2500/day Calorie OUTPUT =3000/day Negative Energy Balance 2500-3000 = -500 Body Weight Decreases

Negative Energy Balance Energy In: 1500 kcal Energy Out: 2000 kcal Negative Energy Balance: Energy Input < Energy Output 1500-2000= -500 Result: Body Weight Loss

Energy Balance People become confused by the concept of energy balance… They expect one method to work for everyone with equal success. Not true! There is a difference in energy use (calories burned) in each person’s body. This is why some people can “eat all they want” and others “look at food and put on weight.”

Energy “OUT” There are two main categories of how energy is used in the body: Basal Metabolic Rate (BMR). Physical Activity.

Energy “OUT” Basal Metabolic Rate (BMR) BMR is the largest factor in determining overall metabolic rate. It determines how many calories you need to maintain, lose or gain weight. Definition: the energy used when the body is in a fasting state (not eating for 12 hours or more) to keep a resting, awake body alive in a warm, quiet environment.

Energy “OUT” 1. Basal Metabolic Rate (BMR) The processes involved include maintaining: a heartbeat, respiration, body temperature, digestion and other functions. Basal metabolism varies 25-30% between different people.

Energy “OUT” Basal metabolism is influenced by a combination of genetic and environmental factors that include: Genetics Gender Age Weight Height Body Surface Area Body Fat Percentage Diet Body Temperature External Temperature Glands Exercise

Energy “OUT” GENETIC FACTORS include: Genetics- Some people are just born with faster or slower metabolisms. Gender- Men have a greater muscle mass and a lower body fat percentage; they generally have a higher metabolic rate. Age- BMR is higher in childhood then in adulthood.

Energy “OUT” GENETIC FACTORS include: Height- Tall people have more body surface. Heat is lost through this body surface. The more body surface, the more heat is lost. The more heat lost, the more energy needed to maintain body temperature. Glands- The thyroid is key BMR regulator. It makes the hormone, Thyroxin. This hormone speeds up the metabolic activity of the body. The more thyroxin produced, the higher the BMR.

Energy “OUT” ENVIRONMENTAL FACTORS include: Diet- Starvation or abrupt calorie reduction can dramatically slow BMR by up to 30 percent. External Temperature- As the outside temperature gets colder, the metabolic rate will slow down to maintain the internal body temperature. This is how the body conserves energy. Exercise- Physical exercise burns calories, and helps raise your BMR by building extra muscle. Strong muscles burn more calories, even when you sleep!

Energy “OUT” A combination of genetic and environmental factors include: Weight- The more you weigh, the higher your BMR (more surface area). Body Surface Area- Same as for height. Body Fat Percentage- The more body fat a person has, the lower the percentage of lean muscle, the lower BMR they have. The more body fat a person has, the more likely that body will hold onto excess calories and store them as fat. Body Temperature- The higher the body temperature, the more calories that are burned in a resting or active state.

Energy “OUT” Physical Activity: It is an environmental factor. It is based on lifestyle choices, not genetic factors. It burns calories in addition to the calories burned by BMR. Physical activity increases the number of calories needed to be consumed to maintain the same body weight. Not all activities use the same amount of energy, however. Reading a book requires less energy than walking around the block. Walking up stairs requires more energy than taking an elevator.