Human Nutrition 1992 Official food guide pyramid. May undergo revision, separating out different types of fats and carbs. Calories - amount of energy required to raise the temperature of a gram of water 1 degree C. It is such a tiny amount that we scale up using kilocalories (kcal). Calories are used to generate ATP and 60% are lost as heat to the environment during life’s activities.

Metabolic Rate - the rate of energy consumption by the body = BMR + additional energy consumption above BMR) Basal metabolic rate (BMR) = amount of energy just to maintain basic body functions Human BMR = 1300 to 1800 kcal/day. See p. 495 on how to figure your caloric balance. Food labels (see left) -FDA requires lists of ingredients in order from greatest amount to least, by weight. Also lists key nutrition fats: serving size, Calories, fat, cholesterol, carbs, fiber, protein, vitamins, minerals.

Essential nutrients-substances which cannot be made from any other materials - the body needs to receive them in preassembled form. Ex: 8 Essential Amino Acids - (see left). 12/20 can be made from other compounds. 8/20 must be obtained from the diet. (Infants require a ninth, histidine.) Meat, eggs and milk are “complete.” Plants are “incomplete.” Eat a variety of plants. Ex: grain + legumes ; Beans + corn tortillas; peanut butter + bread. Rice + tofu. Vitamins, Minerals, & Essential Fatty Acids - read text p. 496-498.

Nutritional Disorders Malnutrition -a deficiency of one or more of the essential nutrients. Cause: Inadequate intake or medical problems. Most = protein deficiency. Victims likely to be retarded in mental and physical development. Ex: Kwashiorkor - (see left) inadequate protein intake. Deficiency in blood proteins causes swelling of the belly and limbs. Undernutrition - body breaks down its own molecules, muscles, brain proteins. Obesity - inappropriately high ratio of weight to height. 1/4 of Americans Fat cravings - cheeseburgers, chips, fries, ice cream, candy. A selection advantage in our evolutionary history when starvation and famines were a danger??

Eating Disorders - a common cause of undernourishment. 3% of U.S. females develop anorexia or bulimia at some time in their lives. Anorexia - self-starvation due to intense fear of gaining weight, even when person is underweight. Bulimia - behavioral pattern of binge eating followed by purging through induced vomiting, abuse of laxatives, or fasting. Both - obsession with body weight and shape. In industrialized countries. Cause -unknown, genes, psychology, brain chemistry, culture. Pop culture & media? Treatment - counseling, medication. Some resume healthy eating habits; some have a long-term problem, impairs health, can cause death.