Weight Loss, Weight Gain and Weight Maintenance

Energy Units

• calorie– Basic energy/heat unit– The amount of heat necessary to raise temp of 1

gram of water 1° C.

• Kilocalorie (kcal)– Basic food energy unit– The amount of heat necessary to raise temp of 1 kg

water 1° C– 1 kcal = 1000 calories

• Calorie is same as kcal

Body Fatness

• Minimal Fat– Males: ~3%– Females: ~12%

• Ideal Fatness– Varies with individual– Varies with type of athlete

Basic Energy Equation

If Energy Consumed is = Energy Expended, then weight is stable

If Energy Consumed is >Energy Expended, then weight is gained

If Energy Consumed is < Energy Expended, then weight is lost

Energy Storage in the Body

• Excess energy in any form is stored– Excess CHO is stored as fat– Excess Pro is stored as fat– Excess Fat is stored as fat

• Must distinguish excess energy from energy necessary for muscular contaction– Liver glycogen– Muscle glycogen– Muscle triglycerides

Source Grams Kcals

Blood Glucose 5 20

Liver Glycogen 100 400

Muscle Glycogen 400 1600

Muscle Triglycerides 300 2700

Adipose Triglycerides 10,000 90,000

Energy Stores in Normal, Sedentary Adults

50 kcal Daily Energy Gain

• 350 kcal per week (0.1 pounds)

• 18,200 kcal per year (5.2 pounds)

• 182,00 kcal per decade (52 pounds)

Food and Weight Loss• The most important factor is the total number

of calories consumed• Carbohydrates and protein consumed in

excess of the body’s need will result in the excess being stored as fat.

• It is more efficient for the body to store fat as fat than to store carbos or protein as fat.– 95% of excess fat calories are stored as fat– 75-80% of excess carbo/protein is stored as fat

Glycemic Index (GI)

The GI reflects the rate of digestion and absorption of CHO

GI =

Blood glucose area after test food

Blood glucose area after reference food

X 100

Glycemic Index

• Measure of how rapidly CHO is digested and becomes available in the blood

• Highest value assigned to glucose (100)

• The higher the value, the faster it gets into the blood

• The higher the value, the greater the insulin response

Problem with Chronic Hyperinsulemia

• Promotes fat storage

• “wears out” the pancreas

• Promotes Type II Diabetes

Characteristics of Fat That Make it Preferential to CHO as a Storage Substrate

• More than 2X as much energy per gram– 1 gm fat = 9 kcals– 1 gm CHO = 4 kcals

• Not hydrated when stored– For every gram of glycogen stored, 3 grams

of water are stored.– Average person would have 50-75 additional

pounds as water if fat were hydrated to the same extent as water.

Exercise and Weight Loss

• Regular aerobic exercise may increase BMR

• More calories can be expended doing aerobic exercise than any other kind

• The harder you exercise and the longer you exercise, the more calories you expend.

Misconceptions about Exercise and Weight Loss

• To loose fat from a certain area of the body, exercise that particular area

• Exercising at a lower intensity will reduce fat more than exercising at a higher intensity

Tips for Effective Weight Loss

• Weight loss is a long term project. There are no easy short cuts.

• Reduce fat in your diet to less than 30% of total calories

• Reduce total calories by no more than 25% of calories required to maintain weight

• Increase caloric expenditure and REE with regular aerobic exercise???

Weight Gain• Adequate caloric intake

– 2500-3500 kcal per pound of muscle– 1 pound of gain per week or 400-500 kcals

per day

• Adequate protein intake (0.8-2 g/kg)

• Adequate stimulus of skeletal muscle

• Adequate recovery for muscle

• Adequate hormonal environment– Timing of protein intake– Supplements