Healthy body: food as nutrition and energy Reynaldo Barron 8th Grade Science Reference: “Science Interactive Notebooks, Metabolism and Nutrition” by Stephanie Elkowitz.

Healthy body: the basics A balanced diet combined with regular exercise helps in the overall general health of the body Humans require energy to function. Total Energy Needed = (Type/Intensity of Activity + Energy Needed for Basic Life Processes) Humans get the energy we need from the food we eat. Food energy is measured in “calories”.

“Nutrients”: What are they? Living things cannot survive without nutrients. Nutrients are found in the food we eat. Humans use nutrients for energy to fuel all of the processes in the body such as movement, circulation, and reproduction. Nutrients grow and repair body tissues. Humans need (6) major nutrients to survive: carbohydrates, fats (lipids), proteins, vitamins, minerals, and water. The macronutrients are: carbohydrates, fats (lipids), and proteins.

Nutrients: Carbohydrates & fats the main source of energy for the body made of sugar units found in items such as bread, pasta, fruit, and vegetables. Fats (lipids) a very rich source of energy needed to insulate your body, build cells, and absorb vitamins found in meat, cheese, oils, butter, and nuts.

Nutrients: Proteins & vitamins made of Amino Acids which are building components of cells important in building and repairing cells can be a source of energy found in meat, dairy, beans, and eggs. Vitamins help your body grow and function help fight disease, heal wounds, eyesight, and obtain energy from certain foods Types are: A, B, C, D, E, K, etc.

Nutrients: Minerals & water help cells function properly some help build bones and teeth some help maintain a healthy blood pressure Include: Calcium, Potassium, and Sodium found in fruit, vegetable, and dairy foods. Water essential to survival helps transport nutrients to cells, remove waste from the body, and needed for many chemical reactions in the body found in many foods such as fruits, but should be consumed by itself often.

Food: what is it used for? Five important uses for food in the body: Growth—Amino Acids in Proteins are cell building blocks. Repair—Proteins, Vitamins, and Minerals repair damaged or diseased body tissue. Fuel Life Processes—Simple sugars in Carbohydrates provide the energy to fuel cell functions. Create Stored Energy—Fats fill fat cells to insulate the body and act as reserves if the body does not get enough food. Fight Disease—Different nutrients help fight disease and build antibodies to disease agents. For the body to use food (nutrients), the food must first be digested into molecules that are absorbed and transported to cells.

Calorie Needs: How many do you need? Factors that affect the calorie needs of an organism: Species - different animals need different amounts of calories. Size – larger organisms require more energy because of greater body mass. Gender – males generally require more calories than females because of greater muscle mass. Pregnant females require more energy to nurture offspring. Metabolism – individuals with a faster rate of chemical reactions require more energy than those with slower rates. Age – older individuals generally require less food energy. Physical Activity – more activity = more calories needed.

Metabolism: what is it? The sum of all the chemical reactions that occur in an organism. All the chemical reactions that sustain life. All the chemical reactions involved in storing and converting food into energy. Basal Metabolic Rate (BMR) – the amount of energy needed to maintain minimum essential life functions (accounts for 60% of energy used by the body) Controlled by hormones which are chemical messengers. Hormones released by endocrine glands (Ex.: thyroid gland). Rate affected by many factors.

Metabolism: What affects it? Factors that affect metabolic rate: Hormones – chemical messengers that send signals to increase or decrease metabolic rate. Diet – how and individual eats affects rate. Eating too much or too little can slow rate. Age – rate tends to slow with age because of decreased muscle mass. Physical Activity – increased physical activity tends to increase rate. Increased muscle mass also increases rate.

Cellular respiration: burning fuel Remember cellular respiration? Glucose + oxygen yields carbon dioxide, water, and ENERGY in the form of ATP The heart and lungs work together to deliver oxygen-rich blood to the cells of the body and remove the waste product carbon dioxide. The lungs take in oxygen and removes carbon dioxide. The heart and circulatory system delivers oxygen where needed, and removes carbon dioxide. Being physically fit, makes this process more efficient.

The goal: Energy balance A healthy body requires a balance between a healthy diet and physical activity. Food taken into the body does (1) of the following: Be used to fuel metabolic or physical activities Be used into growing body tissues Be stored as fat Energy Balance means Energy In = Energy Out Weight gain if more calories IN than OUT. Weight loss if more calories OUT than IN. Regular exercise is important to maintain a healthy heart/lung system, good muscle tone, and good bone strength.