Understanding digestion will help us understand why eating certain foods causes our blood sugar to rise faster than other foods and why certain foods will cause us to put on weight.
The job of our stomach is to process food. It is an acidic environment. It chomps food with it's muscles till they are pulverized and liquefied. It's a hostile working environment.
Eating foods that the stomach needs to process causes a slower rise in blood sugar levels. Eating foods that have already been processed causes a quick rise in blood sugar. The more work the stomach has to do to get at nutrients, the better. The longer it takes the stomach to do it's job, the better. We want slow, sustained digestion. So that we have a slow, sustained, minimal rise in blood sugar levels.
This is why eating an apple is better than drinking apple juice. This is why eating a baked potato causes such a high rise in blood sugar levels. The baking process has already processed the potato, all our stomach has to do is absorb the sugars, and it can do it quickly.
Why the obsession with blood sugar levels?
When blood sugar levels rise, the pancreas secretes insulin telling our body to store that sugar as fat. That's why! We have to try and avoid this insulin surge. Insulin triggers the fat storage response. All the sugar in your blood stream will be converted and stored as fat.
Eating slowly, or making the stomach process food slowly helps slow down the blood sugar surge and the subsequent surge in insulin. We want as low and slow a rise as possible.
Slowing down digestion and absorption
Certain foods slow down the stomach's digestion process even more. Fiber is one of those foods. Don't peel your apples and cucumbers. All the fiber is in the peel. That's why eating apples is better than drinking their juice. Their juice is already processed, already extracted, and contains no fiber. It causes an immediate rise in blood sugar levels.
You can also add fiber to your diet artificially. Psyllium can be purchased as Metamucil. You can either drink this in water or sprinkle it on your food. It comes in many flavors and can be an easy way to add fiber to your diet. It slows down digestion, and can bind saturated fat and help you eliminate it without having it raise your cholesterol. Either drink a glass of psyllium before your meal, or sprinkle it on your meal.
Acidic foods also slow the stomach's digestion process down. Vinegar is acidic and is a great addition to most foods, especially salads. Sourdough bread is also acidic, though not as much as vinegar. If you had to choose between plain white bread, or sourdough, choose the sourdough.
Fats and proteins also slow the absorption of sugars down. If you are going to eat a small piece of bread, dip it in olive oil. That will slow it down. If you really want a small amount of pasta, make sure there are meatballs or meat sauce to help slow down the carbohydrate (sugar) absorption.
Doing some of these things will help slow down carbohydrate absorption, slow down digestion, decrease the level of sugar in your blood stream, decrease the insulin surge, and thereby decrease fat storage.