Macronutrients in our diet:
Fiber
Fiber is present in fruits, vegetables, grains, and legumes. Fiber is not digestible and has no nutrients or calories. Its value lies in its ability to speed foods through the digestive tract and (possibly) bind them.
Fiber is thought to help remove toxins so they do not harm the intestine. Some types of fiber also help control blood glucose and cholesterol levels.
Fiber is also useful because it helps the stomach feel full, and has semi-laxative properties making bowel movements easier. It is thought to help ward off colon cancer.

Macronutrients in our diet:

Cholesterol
Cholesterol is a waxy, fat-like substance produced mainly in the liver but can also be made by cells (except for red blood cells). The liver produces all of the cholesterol the body needs, but cholesterol is also found in animal foods, such as meats, poultry, fish, eggs, butter, cheese, and milk. (Plant foods contain no cholesterol.)

For transport in the blood, cholesterol associates with certain proteins to form lipoproteins. Cholesterol is present in the membranes of all cells, acts as insulation around nerve fibers, serves as a building block for certain hormones, and is needed for the formation of bile acids, which are required for the absorption of fats from the intestine.

Macronutrients in our diet:

Fats and oils
Fats and oils belong to a group of substances called lipids. All fats are combinations of saturated and unsaturated fats.
Fats are vital for the proper functioning of your body. They are used to store energy, are required for the formation of the membranes of cells to keep their contents within, are converted to important hormone-like substances, and form triglycerides that provide a layer of insulation under the skin.
Since the body cannot manufacture all the types of fats it needs, certain ones must be obtained from foods and are called essential. In addition, dietary fat is needed to help the intestine absorb vitamins A, D, and E.

Macronutrients in our diet:

Proteins
Proteins are substances that make up your muscles, bones, cartilage, skin, and antibodies as well as some of the hormones and all the enzymes in your body. Proteins in food are broken down in the intestine into amino acids, the building blocks for proteins in your body.

The body can manufacture 13 of the 22 amino acids present in proteins; these 13 are called non-essential amino acids because they do not need to be obtained from the diet. The other nine are known as essential amino acids because they must be supplied by the food you eat.

Macronutrients in our diet:
Macronutrients are the big ones, the large food we can see go into our mouths. Micronutrients, which we will talk about later in this series, are the vitamins and minerals contained in the food we eat.

Carbohydrates
Carbohydrates are starches and sugars obtained from plants.

Sugars like raw sugar, and that found in candy, cake and cookies are known as simple carbohydrates, and starches like potatoes, pasta, rice, and whole grains are known as complex carbohydrates.

All carbohydrates are broken down in the intestine and converted in the liver to glucose, a sugar that is carried through the bloodstream to cells where it is used for energy.

Some glucose is converted into glycogen, which is stored in limited amounts in the liver and muscles to meet future energy needs.

Carbohydrates are converted into fat when your calorie intake exceeds your immediate needs and your body’s capacity to store glycogen.

Put more simply, whatever calories you consume but don’t burn, get stored on your body as fat.

It takes only 2,000 surplus calories to gain a pound, but 3,500 to lose one.

Many low carb diets try to stop you from piling on the pounds through the comfort eating which causes us to be drawn towards carbs.

What are calories, exactly?

Calories measure the amount of energy in a food.

The food you eat has different calories, with some foods more caloric than others.

Depending on the type of calories, your body will also use and absorb them differently.

Carbohydrates and proteins contain four calories per gram, fats contain nine calories per gram, and alcohol contains seven calories per gram.

All calories consumed in excess of what your body needs for energy— whether in the form of carbohydrates, proteins, fats, or alcohol—get stored as fat.

Fat tends to make you feel full for a long amount of time, but its effect on overall health is to clog arteries and cause weight gain. The former problem is a big issue because heart disease can often be a silent killer. Being overweight is more obvious, but also tough to deal with, since it only takes 2,000 calories to gain a pound, but 3,500 to lose one.

Carbohydrates, also referred to as carbs, can give you a fast fix of energy, but sugary foods can lead to insulin resistance and diabetes, and tend to leave you prone to all sorts of food cravings and bad eating habits.

In our next article we will look at carbs more closely.

Food is your fuel

Food is your life support system
Food provides not only the energy you need to function every day, but also the nutrients required to build all of your body’s tissues (from your bones to your muscles, fat, and blood).

Nutrients in food are also used to produce substances involved in all the chemical processes that take place in your body millions of times a day.

We take in calories, energy, with our food, and different kinds of nutrients.

There are two broad categories of nutrients:

• Macronutrients, carbohydrates, proteins, and fats, which supply energy and are needed in large amounts to maintain and repair body structures

• Micronutrients, vitamins and minerals, which help regulate chemical processes and build strong bones and are needed only in small amounts.

Fiber, while technically not a nutrient, also is part of a healthy diet due to the way it aids in helping to keep your digestive tract healthy, so you can absorb your nutrients from your food well.

We will look at calories, and then each of these categories in turn in our next installments of Food for Life.