Intermittent Fasting – The 5:2 Diet

The 5:2 Diet is a diet where people eat normally for five days of the week and restrict their calories for two non-consecutive days.

The creator of the 5:2 diet Dr Michael Mosley, is a popular presenter on the BBC who has contributed to more than a dozen series for the international public service broadcaster.

A qualified doctor, documentary maker and an award winning science journalist, Mosley specialises in presentations involving health and the human body such as Helicobacter pylori, parasites, the brain and our digestive system.

After being diagnosed with high cholesterol and type II diabetes, Dr Mosley sought out natural methods to reverse these conditions.

While experimenting on himself with various strict fasting regimes he came up with the popular 5:2 diet, the subject of the very popular documentary Eat, Fast And Live Longer.

You can watch a preview of the documentary here:

Watch the full documentary here – Eat, Fast & Live Longer HD

The intermittent fast involves eating normally but sensibly for five days of the week where you need to stick to the recommended daily calorie intake (2,000 calories for women, 2,500 calories for men).

On the other two days, the recommended daily calories is cut to a quarter – 500 calories (2092 kJ) for women and  600 calories (2510 kJ) for men.

According to Dr Mosley the 5:2 diet works because it is “simple, logical and not too challenging. It mimics in a similar way to the feast and famine lifestyle of cavemen as it restricts calories and gives the body a chance to repair itself.”

Why Do the 5:2 Diet?

• Improved insulin sensitivity – a marker for a reduced diabetes risk.
• Reduction in high blood pressure.
• Improvements in reducing the ‘bad’ cholesterol.
• Animal studies reveal it may reduce the risk of dementia.
• Lose weight. In people who are obese or overweight a study of 115 overweight women showed that those who restricted their calories two days a week lost more fat than women doing a more conventional diet.
• There appears to be repair and maintenance occurring at a cellular level when we are not eating.
• Fasting for short periods may help to give your digestive system a rest.
• Improvement in the biomarkers that relate to breast cancer.

Benefits of Intermittent Fasting

• Unhelpful habits are broken for example grabbing snacks on the run.
• On the normal eating days, appreciation for a nutritious meal is enhanced. On these days energy levels are increased making it easier to continue to eat well.
• The ability to listen and retune the bodys’ hunger and satiety signals are improved. In cases where people are starting the diet in order to loose weight the intermittent fasting will help the bodys’ ‘fat brake’ kick in.
• It can be peaceful and productive. When energy levels are limited on fasting days, utilising the energy you have becomes important and wasteful activities are de-prioritised.
• It allows alternative means of coping to be found other than reaching for food.

Foods Suggested for Fasting Days

The basic principle on fasting days is to eat foods that are high in protein and fibre, as these are the most satiating. That means fish, meat, vegetables.

There are a considerable number of books, apps and websites dedicated to providing meal suggestions for  the fasting days.

Here is a small sample of the websites that are out there:

5:2 diet meal plans: What to eat for 500 calorie fast days

Eat Well – recipes & food ideas

5:2 Diet Recipes: What Can You Eat On The Fasting Days?

It is suggested to avoid alcohol on fast days as alcohol is high in empty calories and will cause an insulin spike.

A Example of a Fasting Day Meal Plan. 

Breakfast

Sultanas, Greek yogurt and almonds
1 tablespoon sultanas: 42 calories
3 tablespoons fat-free Greek yogurt: 24 calories
4 whole almonds with skin crushed: 28 calories

Total calories = 94

Lunch

Chicken miso soup

Ingredients
2 x 15 grams Japanese miso paste sachets
1 chicken breast, skinned and sliced
1 clove garlic, crushed
½ teaspoon grated ginger
8 shiitake mushrooms, sliced
Dash of soy sauce
¼ Savoy cabbage, finely shredded

Total calories = 132

Dinner 

Chinese vegetable chow mein

Ingredients
2 tablespoons groundnut or vegetable oil
125 gram packet of oyster mushrooms, sliced
1 red capsicum, deseeded and sliced
125 gram packet tenderstem broccoli, cut into pieces
1 carrot, peeled and sliced
1 tablespoon soy sauce
1 tablespoon rice vinegar
1-2 tablespoons oyster sauce
300 grams ready-to-use medium egg noodles
1 lime, to serve

Total calories = 170

Snack 

x2 Mandarins

Total Calories = 42

Total Calories for the Day = 438

What about Exercise?

The exercise regimen attached to the 5:2 diet is also based on the lifestyle of our ancestors: lots of walking and short bursts of intense exertion.

People who exercise in a fasted state burn more fat. Additionally exercise can be a useful distraction if a person is feeling hungry.

On fast days avoid endurance training and if you are feeling light headed stop immediately.

Hints to maintain success on the 5:2 diet

• If you want to try fasting, do so safely. Get the OK from your health professional.
• Try to maintain a protein intake of about 1g per kilo of body weight.
• Keep exercising even if it’s just gentle walking.
• If possible it helps to fast with someone else.

Negative Aspects of the 5:2 Diet 

On fasting days women are allowed only 500 calories while men are allowed 600 calories. This equates to an extremely limited daily intake of food.  For example a fasting day could include two eggs and some mushrooms (no toast) for breakfast, then 60g to 80g of poached chicken and a little side salad for lunch, and a small piece of white fish with a little bit of salad for dinner. For many people this extreme caloric reduction may be too much to cope with.

When trying to carry out normal activities such as working, exercising, driving or operating machinery on 500 – 600 calories many people may find that they’re very tired and a bit airy-fairy. Therefore these activities need to be done with extreme caution.

Other concerns of the diet are:

• After fasting there is a possibility of over eating.
• Side effects may include poor sleep, bad breath, dehydration or anxiety.
• Restricting food may lead to nutrient deficiencies if the body doesn’t get all the vitamins and minerals it needs.
• It may not be a sustainable solution as people are unlikely to include fasting in their diet long term.
• Fasting can leave you with less energy which can affect your ability to function in  daily tasks.
• The diet is not suitable for pregnant women, Type I diabetics, children or people recovering from surgery.
• Endurance training during fasting days is not necessarily safe and is not advised.
• There is concern the 5:2 diet may encourage eating disorders amongst vulnerable people.
• The fasting days can lead to lower energy, poor mood and concentration and a preoccupation with food and calorie counting.
• The 5:2 diet takes a lot of discipline. A risk with this diet is that people may lose the weight, then find they cannot stick to the fasting principles and put it all back on again. Yo-yo dieting has been shown to be detrimental and can lead to the weight creeping up over the years.

Final Word

The 5:2 diet may not be for everyone as the idea of intermittent fasting sounds counterintuitive to many.

Dr Mosley has introduced an alternative diet that appears to provide positive health outcomes such as a reduction in blood pressure, blood sugars and cholesterol.

Followers are allowed to eat healthily and normally for five days of the week allowing this diet to be both manageable and flexible.

To ensure success when on the 5:2, it’s important to ensure sensible eating on the fasting days, making sure each meal has a good ratio of protein to slow releasing carbohydrates.

Further Reading

• The 5:2 Fast Diet (official website)
• The 5:2 Diet in the Spotlight
• Insulin Resistance – Why You Can’t Lose Weight
• Cutting carbs can lower cholesterol
• Fat – The Good, The Bad, The Ugly
• Is Coconut Oil Beneficial In Alzheimers Disease?

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