Carb's, Protein and Fat

Carbohydrates:

There are 4 Kilocalories per gram of dietary carbohydrate. Another way of looking at this is that each ounce of complex carbohydrates (i.e. Bread, cereals, pasta, rice, fruit) contains 15 grams of carbohydrates and about 60 calories.

The most basic component of a carbohydrate is glucose (C6H12O6). It is found in many foods as one of the components of complex sugars including sucrose and lactose.

1. Sucrose is glucose with fructose. This is also called table sugar.
2. Lactose is glucose plus galactose. This is commonly referred to a milk sugar. In those people who don't have the enzyme to breakdown lactose (ie Lactose intolerance) symptoms such as gloating, gas, cramps and diarrhea may develop with intake of milk or milk products.
3. Starch is many glucose molecules linked together. It is a plentiful, inexpensive and nutrient dense food found in rice, pasta, grains, beans, and vegetables.
4. Fiber is a diverse group of compounds that make up the structural part of a plant. Fiber is by definition something that the human digestive tract cannot break down making it an “unavailable carbohydrate.” Fiber is also broken down into two types: Soluble and Insoluble. Soluble fiber actually undergoes fermentation in the gut producing gas and short-chain fatty acids that are thought to have significant health benefits. Sources of soluble fiber include: legumes, grains, some fruits, root vegetables, and psyllium.
   Insoluble fiber has water-attracting properties that lead to increased stool bulk, softness, and quicker transit time. Sources of insoluble fiber include bran, nuts and seeds, some vegetables, and the skins of some fruits.

Protein:

There are 4 kilocalories per gram of protein and each ounce of protein contains 7 grams of protein and about 30 calories. Proteins are made up of amino acids. When we eat protein in the diet, the digestion process breaks down the protein into the amino acids which the body then reforms into new proteins. The body can make some amino acids but others it cannot. These are called “essential” amino acids. Sources of protein include meat, fish, poultry, dairy and nuts.

1. Complete protein: a food which contains all of the essential amino acids required for normal growth and tissue maintenance. These include ovalbumin (protein found in eggs), casein (found in milk), and meat/fish/poultry.
2. Complementary protein: foods that when coupled together provide all of the essential amino acids in sufficient quantities. Vegetarians will often follow this practice to acquire sufficient protein. Some examples: rice and black beans, beans and corn, nuts and grains
   

Fat:

Fat has 9 kilocalories per gram. A level teaspoon of butter contains about 4 grams of fat and 36 calories. Fat is stored in the body in adipose tissue. In addition to energy storage adipose tissue appears to have an endocrine (ie hormone) effect as well as structural cushion from trauma. Fat is converted to cholesterol which is then converted to steroid and sex hormones in the body. Fat in the diet slows gastric emptying and gives a feeling of satiety and fullness.

1. Essential fatty acids: These must be obtained from the diet and are needed for normal fat transportation, metabolism, and in maintenance of the function and integrity of cell membranes.
   a) Linoleic acid (an omega-6 fatty acid) found in vegetable oils
   b) Linolenic acid (an omega-3 fatty acid) found in fats and oils such as corn, peanut, soybean, fish, walnuts.
   
2. Fat soluble vitamins: Vitamins A, D, E, and K are fat soluble meaning that absorption of these vitamins requires bile salts for absorption. In people on certain medications or after gastric-bypass surgery, they may have deficiencies of these vitamins due to a deficiency of the bile salts.
   
3. Saturated: by chemical definition have all the hydrogen that the carbon atoms can hold. A rule of thumb is that these fats are usually solid at room temperature. They are also more resistant to going rancid. These fats are generally considered “bad” fats and the American Heart Association recommends limiting saturated fats to less than 7% of total calories per day. Some examples include: palm oil, coconut oil, cocoa butter, whole milk, butter, and lard.
   
4. Unsaturated: Two types include polyunsaturated (liquid at room temperature and in the refrigerator but also go rancid quickly) and monounsaturated (liquid at room temperature but start to solidify at refrigerator temperatures). These are considered “good fats” in that they can help reduce blood cholesterol. Some examples include safflower oil, soy oil, sesame seed oil, olive oil, canola oil and avocados.

Sources:
http://en.wikipedia.org/wiki/dietary_fiber
http://www.americanheart.org/
American Society of Bariatric Physicians: Nutrition for Bariatric Practice Lecture 9/2007