Essential Nutrients

The importance of nutrition is often forgotten. The health of our bodies is impacted by the food (nutrition) we eat. Food is essential to help maintain bodily functions and stay healthy. What we eat can impact our recovery after a surgery. But before reviewing the role nutrition has around a surgical procedure it is worth gaining an understanding of the nutrition basics.

Food is the fuel the body needs to keep functioning. There are seven essential nutrients that the body requires, these include:


They are our main sources of energy as well as help the body stay lean, strong and healthy. There are many different micronutrients, vitamins and minerals, and are critical to ensure the body operates optimally.

Carbohydrates: carbohydrates are the main source of energy during intense exercise, but also sustain bodily functions and are essential for healthy brain function. The below flowchart demonstrates the different forms of carbohydrates.

Fats: fats have often been ‘demonized’ in the belief they make people fat. However, they are an essential part of a balanced diet and have many important roles:

  • They are the main source of energy for low intensity, long duration activities, i.e. walking, resting, even sleeping.
  • They also protect internal organs, repair body tissues
  • They help keep the body warm, by preventing heat loss through the skin.
  • They are vital in the diet for the absorption of minerals and fat-soluble vitamins.

The below flowchart demonstrates the different forms of fats.

Proteins: protein’s main role is to build and repair muscles, however they do have a role as an energy source. This is only in extreme cases, such as severe malnutrition. Protein also strengthens the immune system and regulates metabolism.


Micronutrients are vitamins and minerals. Our body needs vitamins and minerals for many different processes which include maintaining the body’s immune system, breaking down macronutrients for energy and repairing tissues without our body. Having a balance of nutrients across all food groups to enable it to work and perform at its best.

Vitamins: vitamins help the body function properly, there are two categories:

  • Fat soluble vitamins, these can be stored in the body
  • Water soluble vitamins, these dissolve in water and cannot be stored in the body

Minerals: minerals also help the body function properly, there are two categories depending upon the amount required by the body:

  • Macrominerals, these are required in large quantities, and include; calcium, magnesium and sodium.
  • Trace minerals, these are required in small amounts, and include; iron, zinc and fluoride.


The two important ‘nutrients’, fibre and water, are needed for the body. They are strictly speaking, non-nutrients, they are essential substances but play a very different role from the macronutrients and micronutrients.

Fibre: Fibre helps maintain a healthy digestive system and assists the movement of waste through the intestine. A build of waste in the gut can lead to many illnesses. A fibre rich diet will help:

  • Reduce the risk of bowel cancer
  • Lower cholesterol
  • Prevent constipation
  • Preventing obesity by controlling appetite by keeping you fuller for longer

Fibre can be found in whole-wheat foods, i.e. bread, oats, cereals, beans, fruits and vegetables.

Water: water is essential for life. It is recommended we consume approximately 8 glasses of water per day (4 pints). This can be from foods we eat as well as fluids we drink. Staying hydrated can:

  • Curb appetite
  • Prevent wrinkles
  • Allow the liver to process more fats

In relation to exercise, staying hydrated can help prevent fatigue and help regulate your body temperature too.

Macronutrients and General exercise

During any activity, muscles are being used to produce the movement. Muscles require energy to fuel them, which is supplied from the food that we eat. Energy will be gained from different sources, depending upon the intensity of the activity.

A low intensity activity will primarily get their energy from fats. Fats are used because they provide a larger amount of energy, per gram, compared to other sources. With the lower intensity activity there is more time to gain the energy, which gives fats time to break down to release energy.

However, as the activity intensity increases the energy source changes. Energy is required more immediately, which does not allow fats enough time to break down and release energy. Carbohydrates are stored more locally, muscles and liver, and are broken down quicker, therefore become the energy source. However, because they provide less energy, per gram, they do deplete quicker than fats, then fatigue will set in.

The body needs the right nutrients to repair after exercise. During exercise additional stress is placed on the body, which causes micro-tears within the muscles and presents as muscle ache after a training session. Therefore, it important the diet provides enough protein to build and repair the muscles, ready for the next training session.

Nutrition and exercise examples

The nutritional requirements of an endurance athlete differ from those completing a strength program. An exercise program based heavily around endurance events, i.e. long distance running, cycling or swimming will require higher amounts of carbohydrates to ensure the individual has enough energy for the whole session. They will also need higher intake of protein compared to a sedentary person to maintain muscular strength endurance.

However, an exercise program aimed at increasing strength and power will still require carbohydrates to ensure enough energy is available for training. But their dietary focus will be based on a higher intake of protein to ensure muscular growth and repair is optimized.

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