You do not need to consume any of the simple sugars (glucose, maltose, dextrose, sucrose) as long as you consume more complex molecules which can be broken down into those sugars. These sugars are what your cells use to respire.
Cell Respiration:
Step 1.) Glycolisis: 1 Glucose molecule is broken down into two Pyruuvic Acid Molecules
Step 2.) Krebs Cycle: The Pyruvic acid Molecules are further broken down
Step 3.) ETS (Electron Transport System): Through a series of electron carriers, the energy from the complex molecules is converted into Adenosine Triphosphate (ATP)
To say that no glucose is needed in your body period, is a lie. If your blood sugar drops too low, you die. You need carbohydrates to survive, there is no way around it. The number of carbs you consume, however, is the problem for most.
The entire problem revolves around energy density per gram and cubic centimeter (cc) of food. Let's say you consumed a pill with a mass of one gram, a volume of one cc, and which contained 100 calories. If you ate 20 of these, you'd be 'full'. However, your stomach relies on volume and weight, not energy density, to determine that point.
Thus, you could eat 20 of these each and every meal, and over the course of a day consume 6,000 calories (20 pills per meal x 100 calories per pill x 3 meals = 6,000 calories per day). To say the least, you'd become enourmous very quickly. Most foods (apart from MREs) are far less dense, thankfully.
Thus, if you eat energy dense foods, you'll have to feel 'hungry' all the time. If you consume foods with a good energy density, you'll feel 'full' and consume the correct number of calories.
Don't believe me? Try this experiment at home.
Eat 6,000 calories as quickly as possible, with a minimum of weight and volume of food. Then try to not eat for the next three days- the hunger pangs will be fierce, even though you have enough 'fuel' and will not starve.
-Penguin
