The introduction of cereal grains in the human diet started us on the road to obesity, diabetes, atherosclerosis and all manner of ills of modern civilization.

Cultivation of grains and starchy roots introduced large amounts of carbohydrates into the human diet on a regular basis.  Prior to that development, early humans got sugar only occasionally in the form of wild fruit or honey, and starch only occasionally in the form of wild nuts. This change required the pancreas to work much harder, because insulin is needed to maintain the blood sugar levels in the healthy range. High levels of blood glucose are toxic and must be cleared rapidly to maintain normal body functions. Insulin facilitates transport of glucose from the blood into cells. Insulin also encourages the body to store up calories as fat.

In some people, frequent outbursts of insulin from the pancreas may encourage cells to decrease their sensitivity to that hormone. They become insulin resistant. Insulin resistance is associated with stubborn obesity, abnormalities of blood fats, high blood pressure, diabetes and cardiovascular disease, including increased risk of death from heart attacks and strokes.

The problem with the human diet today is a drastic lowering of the quality of carbohydrate foods as a result of modern food technology, especially the refining and processing of whole, natural carbohydrates, turning them from slowly-digested carbohydrates to quickly-digested carbohydrates. 

Consider two innovations: flour and corn syrup. Modern flour comes from high-speed mills that replaced traditional millstones in the early 1800s. The new mills generate much more heat, so flour coming from them is spoiling more quickly. Spoilage of ground grains results from rancidity (oxidation) of the oil contained in the embryo (germ) of the seed; oxidation is much accelerated by high temperatures. The solution was to remove and discard the embryo and to remove the seed coat (bran) whose fiber interfered with the new milling process. The result was white flour -- superfine particles of starch.  White-flour products are one of the unhealthiest creations of food technology.  Foods made from it cause bursts of high blood sugar (hyperglycemia) and corresponding bursts of insulin secretion (hyperinsulinism).

Corn syrup is a more recent invention. Food technologists learned to make syrup from cornstarch by boiling it with acid under pressure. This product is cheaper than sugar obtained from sugar cane and sugar beets and much loved by manufacturers, who put immense quantities of it into soft drinks, juice, salad dressings, jams, jellies, ice cream and many other foods.

Several factors influence how fast a particular carbohydrate raises blood sugar. One is the chemical nature of the carbohydrate.  The body is very efficient at processing glucose but it has a limited ability to handle fructose, found in fruits and honey.

There is a great increase in consumption of fructose, which is unprecedented in human history. However, the body does not handle large amount of fructose well -- a severe derangement of liver function results. There is also evidence that high intake of fructose elevates levels of circulating fats (serum triglycerides), increasing risks of disease of the heart and arteries.

The introduction of refined and processed carbohydrates brought about disastrous effects.  American fast foods, especially white bread, white rice, soft drinks, snack foods, pastries and candy are resulting in obesity, hypertension, diabetes and heart disease -- the diseases of Western civilization.

Most breads raise blood sugar levels very quickly, not because of the chemical nature of wheat starch, but for two mechanical reasons:

1.      The fine particle size of wheat flour gives digestive enzymes great surface area to work on.

2.      Action of yeast.

By contrast, pasta does not raise blood sugar levels as quickly as bread does, because it is made of Durham semolina and does not contain yeast.

The more a food is processed beyond its natural state, the less processing your body has to do to digest it.  And the quicker you digest your food, the sooner you are hungry again and the more you tend to eat.

The blood sugar (glucose) level acts as hunger barometer – when blood sugar is low we feel hungry, whether or not we have burned the calories that we’ve previously eaten. If blood sugar fluctuates widely throughout the day under insulin’s influence, the net effect may be an excess intake of calories, causing us to gain weight.

Our fundamental problem is that we are eating foods that are too easily digested by our bodies.  We need to slow down the digestive process so we feel hungry less often.  How can we do that? Well, we have to eat foods that have not been highly processed and, therefore, break down at a slow and steady rate in our digestive system, leaving us feeling fuller for longer. How do we identify slowly-digested foods?

·         The first clue is the amount of fiber in the food; it takes much longer to break it down, so it slows down the digestive process. There are two forms of fiber: soluble and insoluble. Soluble fiber is found in foods like oats, barley, beans and citrus fruits, and has been shown to lower blood cholesterol levels. Insoluble fiber is important for normal bowel function and is found in whole grains and most vegetables.

·         Fat, like fiber, slows down the digestive process. When combined with other foods it becomes a barrier to digestive juices. It also signals the brain that you are satisfied and do not require more food.  Fats prolong the process of digestion by slowing down the stomach’s secretions of hydrochloric acid and so fats create a longer-lasting satiety or sensation of fullness after a meal. Excessive fat intake will cause abnormally slow digestion and absorption, resulting in indigestion. Fats and oils in excess increase the tendency for constipation in the average person by slowing down the emptying time of the stomach and reducing the peristaltic action of the intestines. 

·         Protein also slows down the digestive process. Protein is the most filling of all the nutrients.  It is much more effective than carbohydrates or fat in satisfying hunger -- it will make you feel fuller longer, which is why you should always try to incorporate some protein in every meal and snack.                                                                                              You can feel most satisfied after a meal when the foods are of appropriate nutrient proportions.  Strive for adequate protein, fiber, healthy fats and unprocessed or minimally refined carbohydrates (slowly digested) in each of your meals.

• Acids in foods -- lemon juice, acidic fruits (such as tomatoes), vinegar, wine, sourdough bread -- slow down the rate of digestion and lower blood glucose levels.

All refined carbohydrates, either starch or sugar, should be practically out of our diet.

• The majority of carbohydrate calories should come from less refined, less processed foods, which makes them slowly digestible.  The processed foods are also low in fiber and other micronutrients.
• It is desirable to eat some slowly digested carbohydrates with most meals, such as whole grains, beans, vegetables and some slower digested fruits like berries, apples and cherries as opposed to tropical fruits like mangoes, papayas, pineapples and bananas.
• If you eat quickly digestible foods, eat them in moderate quantities and balance them by adding some slowly digested foods at the same meal.
• Reduce the impact of quickly digested foods by eating them as part of mixed meals, including fiber and acid, such as lemon juice.
• Replace white and whole-wheat flour bread with dense, grainy breads.
• Eat firmer-cooked (al dente) pasta rather than longer-cooked.