Today, Meridian begins a regular, new column in which Dr. William Lauro, a family practice doctor, answers your health and medical questions. If you have questions you would like Dr. Lauro to answer, send them to [email protected] .
Dear Dr. Lauro:
I am so confused by all the diets out there. Can you suggest an effective yet safe diet? I have heard high protein and low carbohydrate diets are the best. Is that true? Also, how do these modern diets square with the Word of Wisdom?
Is there anything more confusing these days than what constitutes an effective and healthy diet? Everyday we hear testimonials praising one diet over another. We hear promoters pushing pills that break up fat, break down fat, shrink fat cells, or “bust” carbohydrates. You can’t turn on a morning TV show without some “expert” extolling the virtues of yet another new, super-effective diet. But which one is best for me and my family?
Dr. Lauro Responds:
Before we can answer the question we must first familiarize ourselves with the basics of food science. There are three main components to the food we eat: carbohydrate (otherwise known as sugars, starches and fibers); protein (which can originate from either animal or plant sources); and fat (also known as “lipids” and also present in the diet in many different types). In addition to these three basic components we also consume various minerals such as sodium (salt), calcium, magnesium, and various other “trace” elements and vitamins.
Sugars are the simplest form of carbohydrate. They are sweet to the taste. They also are easily and rapidly digested and absorbed by the body. Because of this rapid absorption, blood levels of sugar rise quickly after ingestion. On the other hand, starch is a compound made of multiple sugar molecules joined together in a long strand and do not taste sweet. Starches are absorbed and metabolized by the body at a slower rate than simple sugars because they must be broken down into their component parts before entering the bloodstream. Thus when one ingests a starch the “blood sugar” levels rise much slower and more uniformly than when one eats a simple sugar.
Starches can either be refined or unrefined. Refined starch is white in color because the fiber has been stripped away and the product has been bleached (white breads, pastas, and rice for example). Refined starches are absorbed faster than non-refined.
A fiber is a starch that is broken down even slower or, in the case of the “non-digestible” fibers such as cellulose, not broken down at all by the body. These non-digested fibers are cast off into the stool, which provides bulk, which is very healthy. Our main sources of fibrous carbohydrate are vegetables and some fruits. Also, because fiber is so slowly digested, it causes one to feel full longer.
When carbohydrates are ingested, blood sugar levels rise causing the release of insulin, a growth hormone necessary for the metabolism and storage of sugar and fat in the body. When we eat simple sugars, insulin levels rise rapidly. As insulin works, sugar is quickly cleared from the bloodstream and converted to a compound called glycogen in the liver, which is then stored for future use. Sugar is also readily converted into fat and stored in fat cells (weight gain). These blood sugar fluctuations (initially high after ingestion and then low after insulin’s effect) can cause people to feel tired, moody, irritable, and hungry before they should. They crave carbohydrate even more as their blood sugar drops, and thus a vicious cycle is established.
Sugars are the initial source of energy for the body. They are quickly and easily burned in the cells. When sugar levels begin to be depleted, the body turns to fats stored in fat cells for its energy source. Fat can be converted to sugar in the body when needed. When fats are broken down they release “ketones” in the bloodstream. One should note that the calorie content of carbohydrate is 4.5 calories per gram.
Proteins are the building blocks of most structural tissues (muscle, connective tissue, skin, etc). They are composed of smaller molecules called amino acids hooked together in long chains. Proteins are absorbed and metabolized very slowly. Once in the bloodstream they are taken to the liver, processed, and stored for future use. They are essential to life because amino acids cannot be manufactured by the body. Because proteins are slowly metabolized they cause one to feel full longer (less hungry). The calorie content of protein is 4 calories per gram.
Fats are composed of triglyceride and cholesterol. After fats are consumed they are digested, metabolized, and stored in fat cells for future use. Triglyceride is the primary storage form of energy for the body but is utilized only after sugars have become depleted. Triglyceride is the marbling ones sees in meat. It is also that gelatinous mass that accumulates around our waists. Cholesterol is a waxy, hard fat and is the building block for most hormones. It exists in the body in several forms, some of which are healthy (HDL cholesterol) and some very unhealthy (LDL cholesterol).
Triglycerides can be “saturated” or “unsaturated”; the former comes mainly form animal sources and is readily converted by our bodies into bad LDL cholesterol. Unsaturated fat is not converted as readily into cholesterol.
Fats, when elevated in the bloodstream, are irritating to the blood vessel wall and can cause the arteries to become inflamed, scarred, calcified, and narrowed. Elevated blood fat (both cholesterol and triglyceride) is a major risk factor for cardiovascular diseases such a heart attack and stroke. Fats are digested and metabolized very slowly and thus they, like protein, make one feel full longer. Fats have a calorie content of 9 calories per gram (double that of protein and starch).
Regarding the minerals we consume, salt is ingested in the greatest amounts and is also the biggest health offender. Too much salt causes water retention, which then raises blood pressure. Calcium has many beneficial effects such as building bone and lowering blood pressure. There are also reports that calcium helps premenstrual syndrome. Trace minerals and vitamins are essential but usually plentiful in the average diet.
In summary we can make some observations that will be useful to us as we discuss a healthy diet in our next article:
1) Simple carbohydrates are called sugars. When eaten they are rapidly absorbed into the bloodstream, causing a rise in the hormone insulin which acts to clear sugar and fat from the blood and to be stored in the tissues for future use. This causes weight gain. The rapid fluctuations in blood sugar levels (first up and then down) can cause one to feel tired, moody, irritable, and hungry;
2) Refined starches (those that have had most of the fiber stripped away) are only a little better than simple sugars. These refined starches are the “white” starches and have about the same effect as sugar in relation to rapid absorption and consequent blood sugar rise, but to a lesser degree;
3) Sugar and starch are readily converted into fat (triglyceride) in the body for storage in fat cells;
4) When we consume excess carbohydrate our bodies burn these compounds for energy long before we start burning the lipids stored in our fat cells;
5) Protein is essential in the diet.
However, protein from animal sources can have a lot of saturated fat in them. Lean proteins (white animal meats and plant-based proteins) are much healthier. Proteins are absorbed and metabolized much slower than carbohydrates so one feels fuller longer;
6) Fats are also slowly absorbed and metabolized, making one feel fuller longer, but in excess can irritate and inflame the arterial wall causing vascular diseases such as heart attack and stroke. Some cholesterol types are good (HDL) while some are quite harmful LDL).
7) The average diet has too much salt in it which can be quite harmful by causing water retention and elevated blood pressure.
Our next article, will address an effective and healthy diet employing the facts we have discussed above. Stay tuned.
