Basal Metabolic Rate Quiz

Biochemistry and Nutrition - Energy Balance

• Nutrition is the science that interprets the interaction of nutrients and substances in food to maintain, grow, reproduce, be healthy, and prevent disease.
• Adequate nutrition is critical in patient care.
• Understanding proper food intake is the first step to a healthier lifestyle.
• Nurses play a crucial role in educating clients on healthy eating habits to improve their health.

Definition of Nutrition

• Nutrition is the science that interprets the interaction of nutrients and substances in food, related to maintenance, growth, reproduction, health, and disease of an individual.
• The act of consuming and using food for energy, maintenance, and growth defines nutritional processes.

Definition of Food

• Food, typically of plant or animal origin, consists of essential nutrients: carbohydrates, fats, proteins, vitamins, and minerals.
• Food is digested and assimilated by an organism to generate energy, stimulate growth, and sustain life.

Healthy Diet

• A balanced diet contains macronutrients, calories for energy, and micronutrients for overall nutritional needs.

Classification of Nutrients

• Nutrients are categorized into macronutrients (carbohydrates, proteins, fats, and water) and micronutrients (vitamins and minerals).

Factors Influencing Diet and Food Choices

• Individual preferences and habits significantly influence food intake.
• Understanding these factors is essential in providing optimal nutritional care.
• Nurses are responsible for assessing and recognizing factors that influence a client's eating habits.
• Factors like preference, habit, gender, values, occupation, body image, emotional state, association, age, medical condition, health and nutrition, ethnic heritage and tradition, social interaction, advertising, religious practices and culture, as well as availability, convenience, and economy all influence diet choices.

Physiology of Nutrition

• Ingestion: Taking food into the digestive tract, typically through the mouth.
• Digestion: Mechanical and chemical processes to convert nutrients into absorbable forms. This includes mastication (chewing), deglutition (swallowing), and peristalsis.
• Absorption: The process of digested food products passing through the intestines into the blood or lymph systems.
• Metabolism: The body's conversion of nutrients into energy.
• Excretion: The process of eliminating waste products from the body.

Energy Balance: Input vs Output

• Energy balance is determined by energy input (calories consumed) and energy output (basal metabolic rate [BMR], thermic effect of food, physical activity).
• A balanced energy budget leads to stable weight.
• Energy input must match energy output to maintain weight.
• Food intake equal to physical activity maintains weight.

Body Weight

• Body composition is the proportion of muscle, bone, fat, and other tissues. It's measured based on the relationship between lean and fat tissues.
• Achieving healthy weight involves meticulous management of energy balance. Achieving a balance in your nutritional choices will help to maintain your weight.

Energy Balance

• Balanced energy budget means when the intake and output of energy are roughly equal. A change in energy stores is equal to the energy intake (measured in calories) minus energy expenditure (based on metabolism and physical activity).

Energy In

• Calories consumed per day define energy intake.
• One pound of pure fat contains 4050 calories (9 calories per gram x 450 grams). It's important to remember that body fat contains water, fat, and protein, with roughly 3,500 calories per pound.
• Nutrients are obtained by measuring their heat energy using a calorimeter.
• Caloric content for many commonly consumed foods can be found in composition tables or on food labels.

Energy Out

• Thermic effect of food is an estimation of the energy needed to process food. This accounts for approximately 10% of the total energy intake.
• Basal Metabolic Rate (BMR) is the body's energy use for basal metabolism. Different proportions of body energy are used for BMR and physical activity.
• Physical activity is a significant factor influencing energy expenditure.

Energy Out: Physical Activity, Thermic Effect of Food and Basal Metabolic Rate

• Percentage of energy expenditure during physical activity (25% to 50%).
• Percentage of energy expenditure by thermic effect of food (5% to 10%).
• Percentage of energy expenditure by basal metabolic rate (BMR) (50% to 65%).

Thermic Effect of Food

• The specific dynamic effect of food is energy used for digestion and food absorption.
• Diet-induced thermogenesis increases metabolic rate, but excess food intake can result in weight gain.
• Different nutrients (carbohydrates, fats, proteins, alcohol) have varying thermic effects (5-10% for carbohydrates, 0-5% for fat, 20-30% for protein, and 20% for alcohol).

Factors Affecting BMR

• Age, gender, growth and pregnancy, body size and composition, fasting or starvation, activity, smoking/caffeine, fever/stress, and hormones all impact BMR.
• BMR decreases with age, it's highest in infancy, decreases thereafter during aging, and is related to the ratio of lean to fat tissue (more lean tissue, higher BMR).
• Males generally have a higher BMR than females due to muscle mass, with the difference being greater in older individuals.
• Pregnant women's BMR is higher in the later stages of pregnancy due to fetal metabolism.
• Active individuals have higher BMR than inactive individuals due to lean tissues and increased activity.
• Fasting or starvation lowers BMR as the body conserves energy.
• Smoking and caffeine increase energy expenditure and BMR, although this is not a healthy practice.
• Illness, fever, and stress increase BMR.

What Makes Us Eat

• Hunger is a physiological need to eat.
• Appetite is a desire to eat sparked by sight, smell, or thoughts of food. Appetite is a learned behaviour, affected by experience.

What Makes Us Stop Eating

• Satiation refers to the feeling of fullness that gradually develops during a meal.
• Satiation cues, such as stomach stretching and chemical messages, signal the brain.
• Neurotransmitters produced in response trigger the decrease in eating.
• Satiety determines the duration between meals.
• The perception of fullness influences the duration of eating.

Additional Notes

• Energy balance is the critical factor influencing body weight.
• Individual variation exists in metabolism and energy needs, impacting weight management.
• A balanced diet, combined with regular physical activity, can help maintain a healthy weight. Understanding factors that influence eating habits are necessary to assist clients to achieve success in weight management.