How Diet Impacts on Exercise

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No matter what type of exercise – cardio, resistance, or flexibility – the muscles that you engage carrying it out will rely on the nutrition you provide through your diet. Diet impacts on exercise before, after, and even during training. It also has an impact on your recovery. With a proper diet enabling you to train harder, get fitter and recover faster.

Let’s look at how each element of your diet impacts on exercise  


The predominant component of muscle tissue, protein in your diet impacts on exercise by building new muscle fibres. It repairs those that are damaged during training. Incorporating sufficient high-quality protein into your diet contributes to an increase in muscle mass. Which over time increases size and physical performance when you work out. Proteins also include branched-chain amino acids which aid in muscle recovery. Meaning you are able to train again sooner (and therefore more often).

Different studies suggest varying daily protein requirements. The average however is an amount in the region of 1 gram of protein for each kilo of body weight for a normal person. Rising to 2 grams for someone undertaking a rigorous training regime.

In order to consume this amount of protein you will need to include it in each meal throughout the day. This actually helps you control calories. Protein is more filling than carbohydrate so you will feel fuller after eating. Therefore less likely to indulge in unhealthy snacks between meals and over eat at the next meal time.

Some studies have also shown that eating protein with carbohydrate helps lower the impact on blood sugar spikes.

Good sources of protein include:

  • Poultry – chicken and turkey
  • Red meats – beef and lamb
  • Fish – tuna and salmon
  • Eggs
  • Dairy – milk, cheese, and yoghurt
  • Legumes – lentils and beans

Lean proteins low in trans fats are the healthiest choice. The amount of red meat and processed meat consumed should not be too high.


Carbohydrate in your diet impacts on exercise by providing muscles with the energy required to perform work. With the popularity in low carb diets this essential food type has gained a bad reputation. The issue however is with the type of carbohydrates people consume.

The simple forms of carbohydrate found in sweets and processed junk food should be avoided. They have a negative impact on blood sugar and contain “empty” calories. They do not contain the vitamins and minerals your body needs. Many people believe that it is the increase in consumption of these types of carbohydrates that has lead to increasing obesity levels in recent years.

Instead your daily carb intake should come from the complex carbohydrates found in whole grains, vegetables, beans and to a lesser extent fruits. These types of carbs are digested more slowly. Helping you feel fuller for longer, and supplying energy throughout the day. They also contain far more essential vitamins and minerals than simple carbs.

The exact make up of your daily split between food types varies depending on which research you read. However the consensus seems to be they should make up the majority of your food intake. But should be restricted to the healthy complex variety.

Good sources of carbohydrate include:

  • Vegetables – but not potatoes
  • Legumes – lentils and beans
  • Fruits – choose those high in fibre, avoid juices as they contain no fibre
  • Whole grains – oats, rye and quinoa

Picking the right sources of carbohydrate not only supply your bodies needs for energy, but also provide fibre, vitamins and minerals. Choosing the wrong source will provide you with a number of “empty” calories and blood sugar problems.

 Carbohydrate sources in diet


Fat has been vilified in recent years, with many blaming this food type for the increase in obesity. This is unfair, fats are an essential food group and every healthy diet will include them. There are 3 classes of fats: saturated fats, unsaturated fats, and trans fats. The key is to consume the healthy type.

Saturated fats are in animal products such as meat and milk. They are causes of increases in levels of “bad” cholesterol in the body.

Unsaturated fats are found in fish, nuts, and some types of oil including olive oil, coconut oil and canola oil. These are considered “good” fats and should form the majority of your fat intake.

Trans fats are found in vegetable oil when it hardens such as after frying or baking. They are therefore found in processed foods, junk foods and spreads. These are unhealthy and should be consumed in minimal amounts.

Fat is a source of energy in the body, the fat in your diet impacts on exercise by providing valuable fat stores. These burn after stores of carbohydrate sourced energy are depleted.

Other roles carried out by fats are absorption of vitamins into the body, assisting with blood clotting and managing inflammation.

The body cannot make certain essential fatty acids such as linolenic acid. It therefore relies on diet to supply them.

Fats should make up around a quarter of your daily calories. With healthy unsaturated fats making up the bulk of fat intake.

Good sources of fat include:

  • Fish
  • Eggs
  • Seeds
  • Nuts
  • Avocados
  • Oils such as olive oil and coconut oil

Fat sources in diet

Vitamins and minerals

Support many bodily functions that are necessary for exercise such as muscle contraction and energy production. Low levels of vitamins and minerals will therefore impede your body’s ability to exercise at a decent level.

The oxygen that is carried in your blood stream is bound in an iron-rich protein. If you have low levels of Iron, you will carry less oxygen in your blood. Leading to you become fatigued sooner when you train.

Vitamins and minerals are found in the foods that you eat, especially whole foods that have not been processed. Good sources include meats, fish and vegetables. If you are eating a well-balanced diet you should be getting all of the nutrients you need.



An often overlooked way that diet impacts on exercise is fluid consumption. We are made up of over 70% water, it supports chemical reactions in our body and is vital for us to survive. A human would die of dehydration long before starvation.

When we exercise we lose a lot of fluid through sweat and heavy breathing. Staying hydrated is critically important to be able to maintain activity and perform at our best.

It helps to regulate body temperature. Making sure core temperature does not rise to dangerous levels. Being hydrated also prevents heart rate from becoming too high.


Diet impacts on exercise – timing of meals

Your athletic performance is impacted by what you consume before exercise, and the timing of doing so. Recovery is effected by the food you consume after exercise, and how soon you do.

Too little nutrition before exercise can mean working out with low blood sugar levels, this will impact negatively on your strength and muscle endurance. You should ideally start the day with a breakfast high in complex carbohydrates and protein at least an hour before exercising. Something simple like poached eggs on wholemeal toast with some fruit and yoghurt is ideal.

Pre-work out you should avoid heavy meals and instead consume a snack high in carbohydrate and protein to fuel your exercise. Adding peanut butter to some whole grain crackers or slices of apple works perfectly.

After exercise, it’s important to refuel to aid muscle recovery and replenish energy stores. Eating foods high in protein and easy to digest like fish or poultry will provide the much-needed protein and amino acids to accelerate muscle repair. Also, your energy depleted muscles will need their stores restocked, pair meat or fish with fresh vegetables and some complex carbs like roasted sweet potato.

Common mistakes when considering how diet impacts on exercise

Two very common mistakes are over-estimating the number of calories burnt during a work out, and under-estimating the number of calories consumed over the course of a day.

Sports Scientists have identified an issue labelled “compensation” that affects many people when they begin to exercise regularly. This comes in the shape of a food based self-reward for exercising, under the misconception that they have burnt more than enough calories to justify it.

A 49g bar of Cadbury Dairy Milk contains 260 calories. An average 11 stone or 155lb person would burn the equivalent number of calories walking on a treadmill at a brisk pace (3.5mph) for 30 minutes.

A number of people rather than rewarding themselves with a “treat” make the mistake of falling for clever marketing of companies selling them high energy drinks, gels or power bars.

Energy drinks are often packed with sugar and can contain up to 300 calories per serving – more than that chocolate bar. Even adding a couple of extra pieces of fruit such as bananas or oranges can add 200 calories to your daily intake.


Common dietary myths

Many people believe the key to diet for weight loss is to make sure you consume a limited number of calories. And that would be fair, to a degree…

Remember every calorie is not created equal. Eating 2000 calories made up of refined sugar will produce difference results than a mixture of protein, healthy fats, and complex carbohydrates.

The key is to focus on eating “whole foods”. Foods not processed or refined. A diet that focuses on eating lean meats such as chicken and fish, healthy fats found in the likes of fish, nuts and avocados and carbohydrates from fresh fruit and vegetables, which are high in fibre, is what you should be aiming for.

It doesn’t hurt to have the occasional treat, a bar of chocolate or slice of pizza, but this sort of food needs to be the exception rather than the rule.

 Balanced diet food sources

The wrap up

We hope you have found this article useful, and that it makes a difference – no matter how small – to your diet and exercise regime. Hopefully we have demonstrated how diet impacts on exercise and some pointers to look out for!

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