Low incidence of bowel disease in rural Africans is because they consume around 55 gm of dietary fiber daily, which is more than 2 ½ times the UK average. Fiber cannot be broken down by the body. It comes in two forms; soluble and insoluble fiber. Insoluble fiber helps to bulk the food up and passes through the digestive tract without much interaction. However soluble fiber absorbs water along the way making the digestive content softer and easier to travel. Through this it also slows down the absorption of sugar into the blood and prevents putrefaction of food. High fiber diets support digestive health, manage weight and reduces cholesterol and therefore the risk of cardiovascular disease. There is also a reduced risk of bowel cancer, constipation, diabetes and obesity. Processed foods are typically high in meat, fish, eggs, and dairy products and low in fiber content. 
The ideal daily fiber intake should be not less than 25-30gms. In the UK the average intake is around 15gms. Fiber is only available from plant foods. Whole grain foods, vegetables, fruits, nuts, seeds, lentils and beans are a rich source of fiber. Boosting your dietary fiber is easy enough however, if you are not used to taking too much fiber then it should be added to the diet gradually. Too much fiber too quickly can lead to bloating, abdominal cramps, gas and diarrhea. In addition to increasing your total dietary fiber content, you can also try to choose food options that have higher fiber content. Different sources have varying levels of fiber content and quality. A good way to measure this is by observing how much water is absorbed. Below are some examples of fiber content of some common foods, based on raw or dry foods.
Food amount equivalent to 10gms of grain fiber
| Wheat bran | 23gms (½ cup) | Carrots | 310gms (3 carrots) |
| Apricots (dried) | 37gms (½cup) | Broccoli | 358gms (1large head) |
| Oats | 95gms (1 cup) | Cabbage | 466gms (1 medium) |
| Baked beans | 137gms (small can) | Apple | 500gms (3-4 apples) |
| New potatoes, boiled | 500gms (7 potatoes) | Banana | 625gms (6 peaches) |
Try some of the following;
• Choose whole grain foods e.g. replace white bread with whole wheat bread.
• Replace orange, apple or grapefruit juices, and eat the fresh fruit or vegetable instead.
• Eat fruit and vegetables (including potatoes) with skin on.
• Choose high-fiber cereals.
• Choose romaine lettuce instead of iceberg lettuce.
• Read food labels to compare fiber content.
• Add 1-2 Tbsp of bran, ground flax seed or high fiber cereal in your morning cereal.
• Snack on nuts, vegetables or fruits.
Remember to drink plenty of fluids to accommodate the extra fiber intake.
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References:
Holford P. (2004). The new optimum nutrition bible. The Crossing Press, Berkley.