F = Food that you eat

One of the better things that the health sciences have produced is a basic understanding of the way our food is broken down and then built up into fat. As a result of this we derive the modern day calorie system which you can use to determine how much potential chemical energy your feeding on. Nutrition is an overarching term for all of the nutrients that make up food. The first three nutrients that everyone should know are the macro-nutrients: fat, protein, and carbohydrates.

Fats are lipids belonging to the sub classification triglycerides, other lipids include oils, waxes, and cholesterol. Lipids are hydrophobic meaning that they do not combine with water unless some other catalyst is added, such as soap. They play an important role in storing energy against a future energy deficit. Fat holds the highest chemical energy of the macro-nutrients and it's important to remember that all other macro-nutrients can be broken down and then rebuilt into fat.

http://en.wikipedia.org/wiki/Fat

Protiens are complex molecules that are created by life because they perform basic functions. You could think of them as the building blocks and tools of cells. They are made of amino acids which include the B vitamins, B1 through B12. Eating meat will give you all of the essentially B vitamins, and you can combine vegetables, grains, and nuts to achieve similar results. Protein has the highest overhead required to break them down into either energy or fat. This means that it will be beneficial to increase the amount of protein in our diets when trying to lose weight.

http://en.wikipedia.org/wiki/Protein

Carbohydrates are long chains of carbon also called saccharides or sugars. They are essentially the long term energy storage system for photosynthesis. Plants have varying degrees of carbohydrate use and this correlates to their metabolic value for humans. Plant material that is high in fiber and low in carbohydrates such as lettuce, bell pepper, or celery have fewer calories then fruits such as bananas, oranges and kiwi's.

http://en.wikipedia.org/wiki/Carbohydrate

All of the Macro-nutrients have a certain amount of chemical energy available to us through digestion.

Macro-nutrient KCal per gram
Fat 9-10 Kcal
Protein 4-5 Kcal
Carb 4-5 Kcal

When we want to lose weight, it's better to eat less fat and carbohydrates and more protein. The reason for this is that breaking down protein requires more overhead to break down then breaking down fat and sugar. However this is only part of our nutritional break down. You need fat in your diet because you'd be unable to function mentally without it. It's beneficial to have carbohydrates in your diet because exercise is arduous with a load of cream and fish in your stomach. I personally keep a percentage of 18-30% protein per day, little fat (10-20%), and the rest carbohydrates (45-60%). Start with a ratio of 50% carbohydrates, 30% protein, and 20% fat. If your losing weight then stick to your diet, if your having trouble running increase your carbohydrates, if your not gaining muscle increase your protein. I eat what I want but use feedback which I will talk about later to plan what I eat in advance. Another method I recommend is using the zone diet meal planning method. You can eat some of the foods you love while at the same time getting the protein that will help you feel satisfied. However if you want to be a super athlete then perhaps you'll want a more strict control.

http://www.zonediet.com/

You can lower the fat in your diet by eating lean fish and poultry. It's also important to have lots of variety in your foods. For instance a great meal is a cup of plain unsweetened yogurt and 2 cups of fruit. You can substitute oatmeal for the yogurt. When eating pizza you can substitute the cheese and tomato sauce for pesto sauce then add chicken and Parmesan cheese. Lean ham, whole grain pizza dough, and sauces made with olive oil or cheese substitute can also make your favorite foods more healthy. Finally no introduction to weight loss nutrition would be complete with out talking more about processed carbohydrates.

There are three sorts of carbohydrates, there are complex carbohydrates which include, chopped grains like oatmeal, and vegetables vegetables like green beans and brocoli. Processed carbohydrates tend to be white purified powders of the chemical energy that your body can break down; processed from the fruits, grains, and vegetables. These foods such as flour, sugar, and corn syrup have made food very cheap by increasing the calorie density at the sacrifice of the micro-nutrients and fiber. Simple carbohydrates include, Corn, Carrots and Potatoes. These foods are identifiable by their starchy or sweet nature, they include fruit and they all contain very little fiber. Generally for weight loss it's important to cut out Simple and Processed carbohydrates.