FATS AND OIL
 Fats are solid at room temperature and oil is liquid at room temperature. Fats is mostly found in plants and animals as egosterol, cholesterol, phospholipid, etc. They provide energy for body metabolism which are stored in the adipose tissues of the body.
    Fats can become  rancid(unpleasant odour from fats) which can be oxidative, absorptive or hydrolytic.
Oxidative rancidity occurs when the fat is exposed to the atmosphere or high degree of unsaturation of the fatty acid example is the oxidation of oliec acid to 9-octadecanioc acid
Hydrolytic rancidity occurs when the fat is not stored well in the refrigerated leading to enzymatic breakdown of the fat in the substance. Food that undergo this type of rancidity are cake and other foods containing butter.
  Absorptive rancidity occurs when the fat absorbs odours around it such as diesel, insecticides, etc. As such foods containing fats should be kept far from these substances that may lead to its rancidity and hence spoilage.
 Fats also serves as an insulator of the body, for proper growth and development, for proper physiological functioning of the body. Oil helps for good vision, they add taste to the food consumed, provides healthy cell membranes and provides vitamins A, D, E an K. They also help in regulating of the hormones and gives better skin.
 Essential fatty acids are needed by the human body and they are omega-3 acid and omega-6 acid since they cannot be produced by the body. They play important role in blood coagulation, brain development and control of inflammation in the body.

              SOURCES OF FAT AND OIL
1 oily fish such as mackerel, fin tuna, sardines
2. Nuts
3. Plant oil such as soy, corn
4. Chicken
5. Lard
6. Butter
7. Avocado.

       CLASSIFICATION OF FOOD 
 BASED ON COMPOSITION

     Foods can be classified based on chemical composition into
1. Protein
2. Carbohydrates
3. Fats and oil
4. Vitamins
5. Water and
6. Minerals

                   PROTEIN
 This are nutrients made up of large molecules of amino acids. All proteins are enzymes but not all enzymes are proteins. Proteins helps in growth, in providing supportive and protective structures and tissues, formation of enzymes and hemoglobin,etc.
                         PROTEIN SOURCES
Sources of protein includes
1 eggs
2. Meat
3. Fish
4. Groundnut
5. Beans etc


       

           
                            .

                CARBONHYDRATE
This are class of food which provide energy in the form of glucose(C6H6O12). They are formed from the as a photosynthetic product form plant when they take in carbon dioxide.  A well balanced meal should contain about 60-70% calories of carbohydrate. Also carbohydrate forms a large part of animal feed and it's sources are many.  Some of the sources include:
1. Rice
2.bread
3. Wheat
4. Oat
5. Barley
6. Maize
6. Yam
7. Cassava etc

                 

FOOD

 
                   DEFINITION OF FOOD
Food can be defined as any substance of plant or animal origin that is taken in to provide nutritional support to the body. On this basis, we may say that without food, there will be no nutrition and without nutrition, the body's immunity will break down leading to outbreak of various diseases. It is therefore essential that we not only eat food but a well balanced meal so that we can live an active and healthy life.
 For instance, someone who consumes only starch every day (e.g rice) might end up having nutritional defence leading to malnutrition ( an abnormal condition caused by feeding on low nutrient food or foods of low ration or even on too much food that don't have enough nutrient needed by the body). On this note, noodles is considered a junk food (foods with high calories ranging from carbohydrate, protein to little amount of fibre,  vitamins and minerals). They have low nutritional values and so should not be eaten continually.

                FUNCTIONS OF FOOD
1. They provide oxidative energy
2. They help in repairing of body tissues and conducting body processes
3. They help in providing supportive and protective structures in the body.
   
          CLASSIFICATION OF FOODS

Food can be classified based on
1. There ph
2. There chemical composition or nature
3. Perishability
4. Origin etc
   
                          PH CLASSIFICATION 
 Based on pH scale foods can be classified into the following
 1. High acidic foods: this are foods below pH scale of 3.5 They are considered to be highly acidic. Example includes the juice we get from fruits such as orange juice, Apple juice etc
2. Medium acidic foods: this are foods with pH scale ranging between 3.5-4.5. Example is the fruits we take
3. Acidic foods: this are foods ranging from 4.5-5.0. They include soup, vegetables etc
4. Low acidic foods: this are foods above 5.0. They include meat, fruity vegetables etc.