Heartsavers - Diet
Try to get most of your energy needs
from foods rich in complex carbohydrates and fiber.
Prevention of coronary heart disease.
Carbohydrates and fiber
Carbohydrates are the major source of energy in the human diet.
Plants make carbohydrates by using the basic elements of water and carbon dioxide. Sunlight is required by the plant to make the necessary chemical reactions possible, (it's an endothermic reaction). The plants use some of the carbohydrates to form their skeletal structure, these substances we call fiber. Other carbohydrates are stored in the roots, tubers, fruits and seeds to provide an energy reserve for the plant and to provide energy and nutrients for seedlings.
Fruits tend to contain simple carbohydrates such as sugars, whilst seeds, roots and tubers contain more complex carbohydrates called starches.
So there are three basic types of carbohydrate:
- Simple Carbohydrates: Sugars
- Complex Carbohydrates: Starches
- Fiber: Mainly Non-Starch
Sugars
Simple soluble carbohydrates the most common are: glucose, sucrose, lactose, maltose, fructose and galactose. The digestive system breaks down the various types of sugar into glucose (mainly) which is then absorbed into the bloodstream and distributed throughout the body to provide energy for cells.
Starches
These are complex carbohydrates consisting of long chains of glucose molecules. These are broken down by the digestive system into individual glucose molecules. It takes longer for the glucose to get into the bloodstream when complex carbohydrates are eaten compared to simple carbohydrates. This means you will tend to get a longer and more sustainable energy boost from foods containing complex carbohydrate such as pasta, than sugary foods. Many endurance athletes, such as marathon runners will eat a diet rich in complex carbohydrates to improve their performance.
Some carbohydrates are also stored in the liver and muscles as glycogen and are converted to glucose when needed by the body.
Fiber
The fiber in food is not digested by the body and so provides no nutrients, but nevertheless plays a very important role in human health. An adequate level of fibre in the diet provides bulk for the intestinal muscles to work on, helping food to pass through the gut more easily. This can reduce the risk of a number of diseases such as constipation, diverticular disease and last, but not least, bowel cancer. Also in human population studies it was found that large amounts viscous fiber such as that found in porridge oats caused major reductions in blood cholesterol levels.
Recommended Intake
The World Heath Organisation recommends a total carbohydrate intake of 55% - 75% of daily energy needs (starch and sugar not fibre). You should favour starch over sugars; the UK Department of Health recommend that sugars should comprise only about 10% of daily energy needs.
The average western diet contains too much fat and too little complex carbohydrate, you should aim to reduce your fat intake and compensate with more complex carbohydrates as found in fruits and vegetables.
You should also aim to eat 20 - 40 grams of fibre per day. This is about double the present average intake.
Numerous studies have shown that a high intake of starch and fibre results in a considerably reduced risk of coronary heart disease.