1. Nutrients 

  • Nutrients are substances required by the body to perform its basic functions.
  • Nutrients must be obtained from our diet since the human body can not make them.
  • Nutrients have one or more of three basic functions:

  1. They provide energy
  2. Contribute to body structure, and
  3. Regulate chemical processes in the body.

  • These basic functions allow us to detect and respond to environmental surroundings, move, excrete wastes, breathe, grow, and reproduce.

There are six classes of nutrients required for the body to function and maintain overall health. These are:

  1. Carbohydrates
  2. Lipids
  3. Proteins
  4. Vitamins
  5. Minerals and
  6. Water.

  • Foods also contains non-nutrient that may be harmful such as natural toxins common in plant foods and additives like some dyes and preservatives or beneficial like antioxidants.

Types of Nutrients;

Macro-nutrients

  • The plant-based nutrients which are essential in large quantities as our body cannot produce by itself.
  • These macro-nutrients providing energy and supports the different metabolic system, growth, and development of the body.

Micro-nutrients

  • The  nutrients which are required in very small quantities and are mainly responsible for repairing damaged cell and tissues
  • Prevents from infectious diseases by fighting against the disease-causing pathogens including bacteria, virus, fungi, etc.
  • Micro-nutrients include calcium, iron, vitamins, iron and vitamin C.

Key Functions of Nutrients;

  1. Carbohydrates: Provide a ready source of energy for the body and provide structural constituents for the formation of cells.
  2. Protein: Necessary for tissue formation, cell reparation, and hormone and enzyme production. It is essential for building strong muscles and a healthy immune system.
  3. Fat / Lipids: Provides stored energy for the body, functions as structural components of cells, and signalling molecules for proper cellular communication. It provides insulation to vital organs and works to maintain body temperature.
  4. Vitamins: Regulate body processes and promote normal body-system functions.
  5. Minerals: Regulate body processes, are necessary for proper cellular function, and comprise body tissue.
  6. Water: Transports essential nutrients to all body parts, transports waste products for disposal, and aids with body temperature maintenance.

2.BMI (Body Mass Index)

  • The full form of BMI is Body Mass Index.
  • It is a method of measuring through which individuals are classified into the following
  • categories: obese, overweight, normal weight and underweight.
  • It’s the proportion of your weight in kg (kilogram) to the square of your height in m(meters).
  • People who have high BMI have much more body fat or weight for their height.

Calculation of BMI

1. Convert your weight to kilograms (kg)
2. Convert your height to meters (m) .
3. Square your height in meters.
4. Calculate your BMI according to formula.
5. For example:
Let's say your weight is 70 kilograms and your height is 1.75 meters.
6. BMI = 70 kg / (1.75 m x 1.75 m) = 70 kg / 3.0625 = 22.86
7. Interpretation of BMI
8. Consultation with physician or a dietitian

Interpretation of BMI

1. Underweight: BMI less than 18.5
2. Normal weight: BMI between 18.5 and 24.9
3. Overweight: BMI between 25 and 29.9
4. Obesity: BMI of 30 or greater

Example,

A person weighs 70 KG, and the height of a person is 1.829m. Find the BMI
of the person and Interpret the status.

Solution: BMI = Weight in KG / (Height in m)2
= 70 KG / (1.829)2
= 70 KG / (1.829 x 1.829)
= 70 KG / 3.345241 m2
BMI = 20.9

Status: The Person is in Normal Range (18.5 – 24.9)

3. BMR  (Basal Metabolism Rate)

  • B.M.R is a measure of energy expenditure.
  • It can be defined as the minimum amount of energy that our body requires to maintain its normal processes while being at rest and performing only the vital functions like breathing.
  • An average man has a BMR of around 7,100 kJ (1697 calorie) per day.
  • An average woman has a BMR of around 5,900 kJ (1410 calorie) per day.

BMR defines your basal metabolism rate which makes up about 60-70% of the calories we use (“burn” or expend). This includes the energy your body uses to maintain the basic function of your living and breathing body, including:

  1. Heartbeat
  2. Cell production
  3. Respiration
  4. The maintenance of body temperature
  5. Circulation
  6. Nutrient processing

FACTORS THAT AFFECT OUR BMR

1. Body size – larger adult bodies have more metabolising tissue and a larger BMR.

2. Amount of lean muscle tissue – muscle burns kilojoules rapidly.

3. Amount of body fat – fat cells are ‘sluggish’ and burn far fewer kilojoules than most other tissues and organs of the body.

4. Crash dieting, starving or fasting – eating too few kilojoules encourages the body to slow the metabolism to conserve energy. BMR can drop by up to 15% and if lean muscle tissue is also lost, this further reduces BMR.

5. Age – metabolism slows with age due to loss of muscle tissue, but also due to hormonal and neurological changes.

6. Growth – infants and children have higher energy demands per unit of body weight due to the energy demands of growth and the extra energy needed to maintain their body temperature.

7. Gender – generally, men have faster metabolisms because they tend to be larger.

THERMIC EFFECT OF FOOD 

  • BMR rises after you eat because you use energy to eat, digest and metabolise the food you have just eaten. The rise occurs soon after you start eating, and peaks 2 to 3 hours later
  • This rise in the BMR can range between 2% and 30%, depending on the size of the meal and the types of foods eaten.
     

4. Structure of the Food Pyramid

    1. Base Layer – Grains (Bread, Rice, Pasta, Cereals):

      • Forms the foundation of the pyramid.
      • Includes carbohydrate-rich foods that provide energy.
      • Recommended: 6–11 servings per day.

    2. Second Layer – Fruits and Vegetables:

      • Vegetables: Provide essential vitamins, minerals, and fiber.
        • Examples: Spinach, carrots, broccoli.
        • Recommended: 3–5 servings per day.
      • Fruits: Rich in vitamins, especially Vitamin C, and fiber.
        • Examples: Apples, bananas, oranges.
        • Recommended: 2–4 servings per day.

    3. Third Layer – Proteins and Dairy:

      • Proteins: Includes meat, fish, beans, eggs, and nuts. These help in muscle growth and repair.
        • Recommended: 2–3 servings per day.
      • Dairy: Milk, yogurt, and cheese for calcium and strong bones.
        • Recommended: 2–3 servings per day.

    4. Top Layer – Fats, Oils, and Sweets:

      • Includes butter, sugar, and other high-calorie foods.
      • To be consumed sparingly as they provide little nutritional value but are high in calories.
      • Recommended: Use sparingly.

5. Bomb Calorimeter



  • Bomb calorimetry is a technique used to measure the heat of combustion of a sample.
  • This technique involves burning a sample in a high-pressure oxygen atmosphere, which releases heat that is absorbed by a surrounding water bath.
  • The change in temperature of the water bath is then used to calculate the heat of combustion of the sample.
Uses of Bomb Calorimeter

The main use of a bomb calorimeter is to measure the heat of combustion of a sample, which provides important information about the energy content of the sample. Here are some specific uses of bomb calorimeters:

• Energy Research: Bomb calorimeters are commonly used in the field of energy research to measure the heat of combustion of various fuels, such as coal, oil, and natural gas. This information can be used to calculate the energy content of the fuel, which is important in determining the efficiency of energy production and usage.

• Food Science: Bomb calorimeters are used in food science to determine the caloric content of food products. By measuring the heat of combustion of a food sample, the amount of energy released during digestion can be calculated, which provides important information about the nutritional value of the food.

• Pharmaceutical Research: Bomb calorimeters are also used in pharmaceutical research to determine the heat of combustion of drug samples. This information is important in designing drug delivery systems and in understanding the metabolism of drugs in the body.

• Environmental Testing: Bomb calorimeters can be used to measure the heat of combustion of various materials, including waste and biomass. This information can be used in environmental testing to determine the potential for air pollution and greenhouse gas emissions.

6. Meal Planning 

Meal planning is the process of organizing meals in advance to ensure a balanced diet, save time, reduce food waste, and manage expenses. It involves selecting recipes, deciding portions, and preparing a schedule that aligns with nutritional needs, dietary preferences, and daily routines.


Steps for Effective Meal Planning

1. Assess Nutritional Needs
Understand dietary requirements based on age, health, and activity levels.

Include a balance of carbohydrates, proteins, fats, vitamins, and minerals.


2. Set Goals
Identify the purpose: weight management, improved health, or convenience.

Consider dietary restrictions (e.g., vegan, gluten-free, low-sodium).


3. Create a Menu
Plan meals for a week, including breakfast, lunch, dinner, and snacks.

Incorporate variety to ensure all nutrients are covered.

Balance food groups using guides like the food pyramid or plate method.


4. Inventory and Budget
Check what ingredients you already have at home.

Plan meals around seasonal and cost-effective ingredients.


5. Prepare a Shopping List
List items needed for the week based on your menu.

Stick to the list to avoid impulse purchases.


6. Batch Cooking and Prepping
Cook larger quantities to store meals for the week (e.g., soups, curries).

Chop and prepare ingredients in advance to save time on busy days.

7. Nutrition disorders


1. Malnutrition


Malnutrition is an imbalance between the nutrients your body needs to function
and the nutrients it gets. It can mean undernutrition or overnutrition.

• One can be malnourished from an overall lack of calories, or might have a protein,
vitamin or mineral deficiency.
• One might also have more excess calories than your body knows what to do with.

2. PEM (Protein Energy Malnutrition)

• Protein-energy malnutrition or PEM is the condition of lack of energy due to the
deficiency of all the macronutrients and many micronutrients.
• It can occur suddenly or gradually.
• It can be graded as mild, moderate or severe.
• In developing countries, it affects children who are not provided with calories
and proteins.
• In developed countries, it affects the older generation.
• PEM is primarily of two types:
1. Kwashiorkor
2. Marasmus