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Diet Diaries: Pros And Cons

Avatar for Hadyn Luke Hadyn Luke posted this on Monday 4th of February 2013 Hadyn Luke 04/02/2013


Diet Diaries: Pros And Cons

Here is a link to a nutrition diary you can use yourself or a personal trainer can use with their clients.


Our blog this week focuses on nutrition diaries and their potential benefits.

Any gym instructor working towards a Certificate in Personal Training will take a Level 3 qualification in Nutritional for Physical Activity. This will allow you to offer nutritional advice for physical activity based on your clients’ needs.

However, applying the theory to a real-life client case study can be a difficult process: nutrition is a lifestyle choice and you can’t be with your clients 24/7 to monitor their activity.

One effective way to find out about clients’ eating habits is to ask them to keep a nutrition diary. This should be completed for a minimum of three days, and the more detail it contains, the easier it will be for the personal trainer to make recommendations.


A nutrition diary should include the following information:

  • The exact time the client consumes the food
  • The type of food
  • The quantity of food consumed
  • How the food is cooked – boiled, fried, baked etc
  • The quality of the food – for example a home-made burger or one from a fast-food outlet
  • Fluid intake, including alcohol

A client should also include in their nutrition diary:

  • Energy levels
  • Mood swings

This allows the personal trainer to assess how the food consumed has affected the individual, for example, whether it has made them sleepy or increased their energy levels.


Ideally, a nutrition diary should be filled in throughout the day, each time a client eats something or takes a drink. However, as people have busy lifestyles, it’s not always easy to find time in the day to log these details. A personal trainer should encourage their client to try and make time, as if they leave it until the end of the day, it’s easy to forget details about the food they’ve eaten or how many glasses of water or cups of tea they’ve had.

Another difficulty for a client is to include full and correct information in their nutrition diary, especially with fast food and processed food, although some packaging includes nutritional information and some information can be found online.

Finally, a client may not be 100% truthful in recording what they have eaten – or they may be on their best behaviour for the three days they are keeping the nutrition diary. Equally, a client may have a very different diet Monday to Wednesday from what they eat and drink from Friday to Sunday, so the three days they choose to record is relevant too.

For the personal trainer, analysing a client’s nutrition diary can be a time-consuming activity. Also, even if they keep an accurate, detailed diary, there’s no guarantee that a client will be willing to act on any nutritional advice given by their personal trainer.


A nutrition diary can provide a wealth of information for a personal trainer to analyse. For example, if you know that a client doesn’t eat breakfast, you can encourage them to do so. If they already eat breakfast, you can suggest ways they can improve on the nutritional content.

By analysing the client’s diary, the personal trainer can work out how many calories a client is consuming in a typical day, either manually using a calorie counter or using software that covers a wide range of food. They can also work out if a client has a good balance of protein, carbohydrate and fat in their diet. This means that the personal trainer can give the client more specific recommendations on what they should be eating, rather than handing out generic advice.

Furthermore, the process of keeping the diary will encourage clients to think about what they are eating, whether they are surprised by, for example, how many cups of tea they drink or how much alcohol they consume, or whether they find themselves cutting back because they are recording the results.

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