Anita Badmus 0

Often, when our clients embark on a new fitness regimes they are seeking a quick fix and place their hopes on amazing “new” diets. Some of the popular diets that they might be considering are the detox, paleo, gluten-free and ketogenic diet.

It is important as personal trainers that we understand what our customers are referring to, as any wrong interpretation could be damaging to their health and may not be aligned to the balanced programme of nutrition, strength and movement that they need to meet their specific goals. To help with communication and manage this effectively we’ll give you an overview of each diet below, including the pros and cons of each, along with a list of foods that are allowed and not allowed to be eaten.

Please note: Nutrition is never one-size-fits all and what works for your sister or your best friend may not be the right choice for you.


This diet’s intention is to eliminate the “toxic waste” from our body in order to stay healthy. (Note: The body naturally detoxifies itself via the kidneys, liver and spleen, and it eliminates them through perspiration and waste.)

What can I eat?

  • Fruit and vegetable juices and water
  • Some detoxes allow fresh and frozen fruits and vegetables

What should I avoid?

  • Few allow whole grains and flaxseed
  • Solid foods

What are the pros?

  • Could reduce alcohol and caffeine intake
  • Decreased intake of high-fat and highly processed foods
  • Encourages eating more plant-based foods

What are the cons?

  • Weight loss is from fluid and glycogen (the body’s carbohydrate stores), rather than fat.
  • Severe food restrictions result in loss of energy
  • Weight regain is rapid when diet is discontinued
  • Metabolism slows down, making it more difficult to keep weight off
  • May result in nutrient deficiencies.



This diet is based on foods presumed to have been consumed by our ancient ancestors, primarily ones that could be hunted or gathered. There is no official "paleo diet", but it is generally seen as a low-carb, high-protein diet, with some variations on carbohydrate and meat intake.

What can I eat?

  • Meat, chicken, turkey and pork
  • Fish
  • Fresh fruit
  • Non-starchy vegetables
  • Nuts and seeds
  • Eggs
  • Plant-based oils, such as coconut, grapeseed, olive and walnut

What should I avoid?

  • Grains, including oats, wheat and barley
  • Starchy vegetables (like potatoes)
  • Beans and legumes
  • Dairy products
  • Sugar
  • Processed foods
  • Salt

What are the pros?

  • Could increase fruit and vegetable intake
  • Could decrease intake of processed, high-sugar and high-sodium foods
  • Could lead to weight loss primarily due to limited food choices
  • Simple and doesn't involve calorie counting.

What are the cons?

  • Low in carbohydrates, which is dangerous for athletes and negatively impacts performance
  • May result in nutrient deficiencies
  • High in fat, which could lead to weight gain


This diet excludes foods containing the protein gluten, which is found in cereals like wheat, barley and rye. It is the only treatment for coeliac disease but is also used to treat non-coeliac gluten sensitivity (NCGS), gluten ataxia, dermatitis herpetiformis (DH) and wheat allergy.

What can I eat?

Foods that do not contain gluten, such as:

  • Meat, fish and seafood
  • Eggs
  • Milk and dairy products
  • Fruits and vegetables
  • Beans and pulses
  • Nuts and seeds (including flaxseed)
  • Grains that don’t contain gluten protein, such as corn,rice and sorghum
  • Pseudocereals like amaranth, buckwheat and quinoa.

What should I avoid?
Any product containing gluten protein, including:

  • Grains like wheat, barley, rye and spelt.
  • Any foods processed in a factory that processes these grains.
  • Processed foods like soups, sauces, ready meals and sausages

What are the pros?

  • Relieves symptoms and complications for those with related health conditions
  • Could decrease intake of refined/processed foods

What are the cons?

  • Difficult to follow
  • Restricts people from healthy foods
  • Gluten-free alternatives tend to be more expensive
  • Gluten-free substitutions may be higher in calories.
  • Could increase heart attack risk in people who do not have celiac disease



This diet is a low-carb, moderate protein, high-fat program that uses fat for fuel. It was originally designed to treat epilepsy. It is being looked at as part of a treatment plan for certain cancers, blood sugar control, Alzheimer’s, dementia and now as a weight-loss method. The ketogenic diet, just as the paleo diet, has been moving through the athlete population, especially with endurance athletes.

What can I eat?

  • Meat and fatty fish
  • Eggs
  • Full-fat dairy products, such as butter, cream and cheese
  • Nuts and seeds
  • Oils
  • Avocados
  • Low-carb vegetables, such as leafy greens, asparagus, cucumbers and celery

What should I avoid?
Added sugar and foods that contain it, such as ice cream, pudding and sugary drinks

  • Grains
  • Fruit
  • Beans and legumes
  • Starchy vegetables like root vegetables and corn.
  • Alcohol
  • Milk

What are the pros?

  • Lowers blood glucose levels
  • May decrease inflammation
  • Rapid weight loss

What are the cons?

  • May result in nutrient deficiencies
  • May result in electrolyte abnormalities
  • May increase risk of heart disease
  • May cause lack of energy
  • May result in changes in bowel habits

Now that you are armed with this information regarding some of the trending fad diets, you can help your client make an informed decision and reinforce that the greatest success comes from a balanced nutrition and exercise problem designed by experts that they can incorporate into their life and maintain the changes for the long term.

Help your clients empower themselves regarding health, nutrition or fitness knowledge. Encourage them to do their research and be informed about the programme they are doing, this will aid greater commitment and engagement. The NHS Live Well website is a good place to start, as is the British Dietetics Association (BDA) website. You may also be interested in the government’s Eatwell Guide. We recommend that you consult your GP or a registered dietitian before you start any diet or a new nutrition plan.

By Emily Bailey

Registered and Licensed Dietitian, and NASM Certified Personal Trainer



NHS Live Well. 2017. Top diets review for 2017. Accessed September 4, 2017.
Coeliac UK, 2017. The gluten free diet. Accessed September 4, 2017.
British Dietetic Association. 2014. Food facts: Fad Diets. Accessed September 4, 2017.
British Dietetic Association. 2014. Food facts: Detox Diets. Accessed September 4, 2017.
Diabetes UK. 2017. Ketogenic Diet. Accessed September 4, 2017.
Diabetes UK. 2017. Diet. Accessed September 4, 2017.

Tags: Advice

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Anita Badmus