The 5:2 intermittent fasting (IF) diet, more commonly referred to simply as the 5:2 diet, has become one of the more popular diet plans in recent years.

This diet involves restricting your calorie consumption to 25% of your energy (calorie) needs, two days a week, and eating normally the rest of the time. This means you’re consuming fewer calories – so you will lose weight. One reason for the popularity of the diet is that it allows a certain amount of flexibility, in comparison to low-calorie diets, on most days of the week.

Plus there’s a health bonus. Studies have shown that the diet helps with weight loss and may also reduce insulin resistance, both of which are of particular interest for many people with type 2 diabetes or borderline diabetes.

THEORY BEHIND THE DIET

The idea of the diet is that short periods of fasting prompt the body to repair the damage but not enter a starvation mode of conserving energy.

While the theory has yet to be conclusively proved, clinical studies have shown promising results for the diet, however, it has only been examined over relatively short time spans, of less than a year.

HOW THE 5:2 DIET WORKS

The base of 5:2 intermittent fasting diet is a simple idea. 5 days a week you stick to meeting the daily calorie intake advised for people of a healthy weight, that being:

• 2,500 kcal per day for men
• 2,000 kcal per day for women

For the other 2 days each week, the diet stipulates that you have only around 25% of the values above, which is equal to:

• 600 kcal on these days for men
• 500 kcal on these days for women

The fasting days can be taken at any time during the week; as long as you do not take 2 fasting days consecutively.

BENEFITS OF THE 5:2 DIET

Clinical studies have shown that the benefits of intermittent fasting are largely similar to those of a calorie restricted diets.

The most commonly reported benefits among people from following the 5:2 diet:

• Weight loss
• Decreased levels of triglycerides and LDL cholesterol
• Reduced blood pressure
• A reduction in insulin resistance

Research has shown that periods of fasting can help to improve life expectancy. But also to decrease risks of diseases including nerve disorders, Alzheimer’s disease, and cancer. However, whether these benefits apply to a 5:2 fasting diet cannot be confirmed as long term clinical studies have yet to be performed.

IS THE 5:2 FAST DIET SAFE FOR DIABETES?

While shorter term studies have displayed promise for intermittent fasting diets, the long-term safety of the 5:2 diet is yet to be determined.

As with any diet plan, you should always consult your GP or diabetes health team before making any significant changes to your diet as they could affect blood glucose levels or impact on your medication.

TYPE 2 DIABETES AND THE 5:2 FAST DIET

The fact that intermittent fasting shows evidence of improving insulin sensitivity may be an attractive option for people with a BMI over 25, borderline diabetes (prediabetes) or with type 2 diabetes but not on blood sugar-lowering medications.

The diet may be good for people who can handle single days of significantly restricted calorie intake in preference to modest calorie restriction every day.

On fasting days, the body will be forced to use stored energy from the body, fat and stored sugar (glycogen). This can help with weight loss and may improve blood glucose and cholesterol levels.

If you are on insulin, or hypo causing medication, such as sulphonylureas or glinides, an intermittent fasting could significantly increase the risk of hypos. Your doctor should advise you on whether the diet is appropriate.

TYPE 1 DIABETES AND INTERMITTENT FASTING

If you have type 1 diabetes, following a 5:2 diet could make diabetes management more difficult to achieve. Also could significantly increase the risk of hypoglycemia.

If your health team are happy for you to start an intermittent fasting diet, they may wish to monitor you more closely to reduce the likelihood of hypoglycemia or increased ketone levels occurring.

HOW TO FOLLOW THE 5:2 DIET

Depending on your outlook, the 5:2 diet may be seen as more or less practical than a continuously reduced calorie diet.

The benefit is that on most days you needn‘t consume less than the daily recommended calorie limit. However, some people may find that calorie intakes of 500 or 600 calories a day are too low to be practical.

For best results, the recommendation is to follow basic healthy eating rules. Such as having a good intake of vegetables, fruit, and limiting intake of processed foods where possible.

During the fasting days, you will need to rely on very low-calorie meals to stay within the daily 500 or 600 calorie counts.

5:2 DIET FASTING DAY MEAL IDEAS

An example of good meal picks on fasting days include those based low-fat foods such as:

• Eggs (65 kcal per medium egg)
• Grilled chicken breast without the skin (190 kcal per 100g)
• Prawns (105 kcal per 100g)
• Non-battered white fish (135 kcal per 100g)

Vegetables tend to be low calorie but if you need very low-calorie vegetables, the following vegetables are particularly good options:

• Cucumber (15 kcal per 100g)
• Celery (20 kcal per 100g)
• Bell pepper (26 kcal per 100g).