Secrets of Energy macronutrients

Energy macronutrients provide energy, which is measured either in kilocalories (kcal or calories) or Joules. 1 kilocalorie (calorie) = 4185.8 joules. Energy macronutrients include:

Carbohydrates - 4 kcal per gram

Carbohydrate molecules include monosaccharides (glucose, fructose, galactose), disaccharides, and polysaccharides (starch).

Nutritionally, polysaccharides are favored over monosaccharides because they are more complex and therefore take longer to break down and be absorbed into the bloodstream; this means that they do not cause major spikes in blood sugar levels, which are linked to heart and vascular diseases.

Proteins - 4 kcal per gram

There are 20 amino acids - organic compounds found in nature that combine to form proteins. Some amino acids are essential, meaning they need to be consumed. Other amino acids are non-essential because the body can make them.

Fats - 9 kcal per gram

Fats are triglycerides - three molecules of fatty acid combined with a molecule of the alcohol glycerol. Fatty acids are simple compounds (monomers) while triglycerides are complex molecules (polymers).

Fats are required in the diet for health as they serve many functions, including lubricating joints, helping organs produce hormones, assisting in absorption of certain vitamins, reducing inflammation, and preserving brain health.

Macronutrients that do not provide energy

These do not provide energy, but are still important:

Fiber

Fiber consists mostly of carbohydrates. However, because it is not easily absorbed by the body, not much of the sugars and starches get into the blood stream. Fiber is a crucial part of nutrition, health, and fuel for gut bacteria.

For more details go to "What is fiber? What is dietary fiber?"

Water

About 70 percent of the non-fat mass of the human body is water. It is vital for many processes in the human body.

Nobody is completely sure how much water the human body needs - claims vary from 1-7 liters per day to avoid dehydration. We do know that water requirements are very closely linked to body size, age, environmental temperatures, physical activity, different states of health, and dietary habits; for instance, somebody who consumes a lot of salt will require more water than another similar person.

Claims that 'the more water you drink, the healthier you are' are not backed with scientific evidence. The variables that influence water requirements are so vast that accurate advice on water intake would only be valid after evaluating each person individually.