If you are interested in your diet, whether it is for weight loss or just for a healthier diet, you will need to know a few things about the 3 main food groups: protein, carbohydrates, and fat. In this article I will tell you what each of them is, why you need them and in what foods they can be found.


Protein is part of every living cell in your body, including skin, muscles, tendons, ligaments, hair, and the core of teeth and bones. It also plays a role in many other functions, such as hormones (such as insulin), antibodies that fight infection, and red blood cells that carry oxygen throughout the body. One thing it’s not used for often is power production. Although it can be very easy, this only occurs in cases of extremely intense physical exertion or hunger, where there are not enough carbohydrates available.

It is made up of the so-called essential amino acids and non-essential amino acids. Nonessential amino acids can be produced in the body and there are 12, but essential amino acids cannot and all 8 must come from the food we eat.

Protein sources include meat, eggs, fish, cheese, and milk, but also nuts, beans, soybeans, oatmeal, lentils, and peanut butter. Obviously, there is no reason why a vegetarian should not get enough without resorting to supplements.

How much is enough?

Well that depends on your weight and your activity level. The protein requirements of someone who does not have a physical job and who does not exercise can be calculated by multiplying their body weight in kg by 0.8.

So for a 60 kg (132 pound) individual, this would be 48 g.

However, if you exercise regularly, this could go from the 0.8 figure to something up to 2g per kilo for a serious athlete or bodybuilder.

Protein provides 4 calories of energy per gram and should account for about 15% of your daily calorie intake. A diet in which the protein intake is too low, as is possible with a poor vegetarian diet, can affect the benefits I just mentioned. But before you rush out and stock up on protein shakes, keep in mind that too much has its side effects, too. If you regularly consume 30% more than you really need, you could be doing yourself more harm than good, in some cases causing liver and kidney problems, including kidney stones, which is just one reason why certain high diets should be avoided in protein and low in carbohydrates.


Carbohydrates have 4 calories per gram and should make up about 55% of your diet. They have various uses in the body. The main one is an energy source called glucose that is stored in the body as glycogen. Glucose, which you may have seen as an ingredient in some energy drinks, is known as a simple carbohydrate that you might better recognize as sugar. This is carried into the body very quickly and will not satisfy your hunger for long, which is one of the reasons why it should ideally be avoided if you are trying to lose weight. It also has a quick effect on energy levels, giving a quick physical and mental high that is soon followed by a crash.

In contrast, the other form, complex carbohydrates, take longer to digest and provide a slower, more consistent release of energy and keep you from feeling hungry any longer.

Examples of complex carbohydrates are rice, pasta, potatoes, beans, and oatmeal.

The rate at which each carbohydrate is absorbed is known as its GI, glycemic index. Each food can be assigned a figure between 1 and 100 based on this, with pure glucose being the one that is absorbed the fastest and, therefore, it is assigned a GI of 100. At the other end of the scale, Lentils have a GI of only 21 and therefore would be much better to keep you from being hungry for longer and to maintain a more stable energy level. High GI foods also promote fat storage, and therefore weight gain, by forcing glucose and fats already in the bloodstream into cells for storage.

There are no risks associated with consuming too many carbohydrates, plus too much sugar can lead to diabetes. Not consuming enough will lead to low energy levels, but not consuming enough for prolonged periods can cause serious health risks if taken to the extreme.


Fat has 9 calories per gram and should make up about 30% of your diet, as it actually has many vital uses in the body. These include protection of internal organs, insulation from cold, absorption and storage of certain vitamins, insulation of nerve cells, healthy hair and skin, and also as a source of energy. As you can imagine, not gaining enough weight can cause many health problems, but this is obviously not a problem for most people in the developed world who eat too much. As a result, they suffer from overweight, high blood pressure, and coronary heart disease.

There are 2 types of fat, and although both are a necessary part of your diet, your consumption of saturated fat should be closely monitored. The main source is from animals and is solid at room temperature. Examples include butter, lard, cream, and meats. What makes it so bad is the amount of cholesterol it contains, too much of which can contribute to heart attacks and strokes.

The other type of fat, unsaturated, comes mainly from plant sources and is liquid at room temperature. Examples include sunflower oil, olive oil, fish, and nuts.

Given the uses that fat has in the body, very little, which can come with a diet very low in calories and fat, obviously has consequences. These include not being able to absorb and store certain vitamins, less healthy hair and skin, and an effect on nerve cells.

Basically the opposite of all the benefits I just mentioned.

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