Factors affecting Basal Metabolic Rate Metabolism Factors affecting Basal Metabolic Rate

Definition – Basal Metabolic Rates Amount of energy required by the body to carry on its vital body processes at rest. Body processes: respiration, circulation, glandular activity, cellular activity, and maintenance of body temperature.

Calculating BMR Calculate weight in kg. divide your body weight in pounds by 2.2 Then multiply body weight I kg by 24 hours. This is your BMR This is the minimal amount of calories you need per day to maintain metabolism.

Metabolic Rates?

GENETICS 2 biological parents over weight – 80% chance of overweight children 1 biological parent overweight – 40% chance of overweight children

AGE After the age of 25 the body slowly declines in health Creeping obesity may occur Muscles atrophy, metabolism drops, fat % increases.

SURFACE AREA Tall, slender people expend more energy maintaining body heat than small, round people. Metabolic rate increases to keep body warm

ENVIRONMENTAL TEMPERATURE Exercising or working in extreme temperatures burns more energy thus increases metabolic rate

Hormones Thyroid gland produces a hormone – thyroxin which stabilizes weight Huge change in weight without a change in diet or exercise – have thyroid check

Fasting / Dieting Body thinks it is going into starvation so….. Metabolism decreases so calories are stored as fat Breakdown of muscle tissue for energy

MENOPAUSE During the last 14 days of the menstrual cycle a women burns 200-300 more calories a day Once menopause starts, a woman can gain 10 lbs per year if activity level does not increase

Metabolic Theories Weight Management

Fat Cell Theory Cell number Cell size

BROWN/WHITE FAT Beta(brown) / Alpha(white) Types of Fat Cells BETA – BROWN – BELLY -breaks down easily, dangerous, increases heart disease ALPHA- WHITE -BUTTOCKS -holds on to energy stores except during lactation

SET POINT THEORY Genetics sets your weight. Body maintains its normal weight and body fat with an internal “thermostat” which controls the amount of fat on the body. High versus low setting Despite changes in dietary and exercise habits, the body tends to return to its “old” weight. Body is comfortable around a certain weight and will fight to maintain that weight. Difficult to lose weight especially the last 5-10 pounds. Once weight loss occurs one must maintain the lost weight for 18 months to 3 years. Then must continue the lifestyle change.

Lifestyle Theory People regain their weight as they regain their lifestyles – 2/3rd gain back the weight. The more weight you’d like to permanently lose, the more of your lifestyle you’ll need to permanently change.

YO-YO Diet Theory Dieting causes muscle mass to decrease thus decreasing metabolism. Weight loss is due to water loss and muscle loss. Once one begins to eat “normal” again weight gain occurs due to decreased metabolism * No quick fix! * Must change dietary and exercise habits for life!