- Food supplies people with chemical energy that used used to do work, e.g. moving, thinking etc. It is also needed to maintain and repair the body.
- Nutrients are substances in food that can be digested and absorbed into the body
- Micronutrients: nutrients that are needed in relatively small quantities. These include minerals and vitamins.
- Macronutrients: nutrients that are needed in relatively large quantities. These include fats, carbohydrates and proteins.
- Fats are found in foods that come from animals, with very high levels in bacon, salami, crisps, cheese and cream.
- Most fruit and vegetables contain little or no fat, except for nuts and seeds which are high in unsaturated fats.
- When digested, fats break down into three fatty acids and glycerol which enter the blood stream. The fatty acids are taken up by a range of body tissues, as well as the blood, while glycerol is taken up by the liver.
- Saturated fats:
- Are solid at room temperature
- Can be found in large quantities in the fat on meat, butter, lard, whole milk and cheese
- Raise the level of cholesterol in the body so therefore increase the risk of coronary heart disease
- Unsaturated fatty acids are divided into monounsaturated and polyunsaturated fatty acids. These are usually liquid at room temperature.
- Monounsaturated fatty acids and polyunsaturated fatty acids are found in oils, such as olive oils and ground nut oil, and soft margarine. They are useful for building cell membranes in the body.
- Trans-unsaturated fatty acids (trans fats) are unsaturated fatty acids that have been partly saturated by adding hydrogen (hydrogenation). This turns the liquid fat into solid fat and prolongs shelf life. Trans fats are believed to raise cholesterol levels in a similar way to saturated fats.
- Fat supplies energy to the body. They contain more energy per gram than any other food (9 calories per gram compared to 4 in carbohydrates and proteins).
- Fats are useful because they can be stored in the body, meaning that by gradually converting stored fat…