Intermittent fasting is a popular diet which includes the cycle of fasting and eating which restricts calorie consumption to 25% or less of your normal daily calorie intake on “fasting” days. There are different types of intermittent fasting like the 5:2 diet. So in simple terms, you eat a lot less for two days a week and you eat the foods you normally would for the other 5 days. Usually there is at least one day’s gap between the two fasting days – fasting on Monday and Wednesday, or Tuesday and Friday. Generally, when somebody consumes less calories and maintain the same exercise levels, they will usually also lose weight. For many people once they start fasting it makes them more aware of what they normally eat on a daily basis and leads them to make healthier choices. Not only does the 5:2 diet help you lose weight, there is lots of scientific evidence that shows that fasting helps the body and cells in the body to repair themselves. The purpose of this diet is twofold, firstly to lose weight and to keep the weight off for the long term and secondly to improve general health. There are numerous long term scientific studies of intermittent fasting that support it and the health benefits achieved. Most people cannot stick with diets for the long term, as either the diet is too hard to follow, or mentally the individual simply gives up. On a non-fasting day you can eat whatever you want, though people should always try and eat as healthily as possible. For fasting days you have do dramatically reduce the number of calories you consume so you should try to avoid processed carbohydrates like white bread, pasta and rice and also cut out sweets, desserts, steaks, and other high calorie foods. During fasting you can eat sensible portions of vegetables, especially leafy green vegetables, smaller portions of lean meats, fish or eggs, soups, salads dressed with vinegar and herbs and replace sweets with fresh fruit and drink lots of water. When preparing food, it is always better to bake, roast, or stem meat and fish, rather than fry in fat. With drinks, you can also drink herbal tea and black coffee, but try to avoid artificially sweetened drinks because it may affect your blood sugar or insulin levels, which is not ideal on a fast day. Usually on a fast day, to maximise benefits, it is better to have 2-3 small portion meals spread during the day so your hunger pangs don’t get too bad. There are pros and cons of any change of lifestyle and diet. The 5-2 diet has the following pros and cons: The positive effects of this diet are that it is very flexible and you can choose which days are fasting days, which days are for normal eating and on fasting days how you want to split up your calorie allowance. Fasting can be planned by eating very small portions across breakfast, lunch and dinner or just having one or two main meals. Because on non-fasting days diet is not restricted and there are no banned foods, this means that you can eat normally for five days each week. Dieting is not such a long process and you only have to be on a ‘diet’ for two days of the week. It’s also easier to stick to when you know that you can eat normally the next day. You won’t feel deprived of anything because you can eat your favourite foods on five of the seven days of the week and not only does it improve health benefits, for example many studies have shown intermittent fasting reduces insulin levels and improve insulin sensitivity. but it also improves your mental health and many people on the 5:2 diet say they have more energy for work and other things they have to do. On fasting days it is important to make every mouthful count and make sure that each meal is as nutritious as possible with the limited amount of calories available on fasting days. The two fasting days encourage you to plan your meals so that you are eating the correct amount of calories.The positive effects can be seen in the many successful stories of people who have lost weight and kept it off as opposed to those who lose weight and put it straight back on afterwards. The other health benefits which occur due to the body healing itself better through fasting are discussed in the scientific section. The negative effects of this diet are although this is a very effective diet, it does have some negative effects. For example, the program is so flexible that some people may find themselves fasting less and less and they may themselves starting to overeat on non-fast days to compensate for the lack of food on the fasting days, making the fasting days pointless. Eating normally for five days may not be effective if your diet is already quite poor. On fasting days you may feel tired, have a lower attention span and energy levels. Fasting days where you only eat 500 calories may encourage disordered eating patterns and may not be sustainable long-term. The 5:2 Diet does not address exercise or mindset, which are essential components to achieve sustainable long-term weight loss. The diet is not suitable for everyone especially if you have insulin dependent diabetes, are pregnant, a child or teenager, or have an eating disorder.Fasting and intermittent fasting has been tested on mice extensively and has been found to extend their lifespan and also “healthspan” – the time they live without catching chronic diseases. Intermittent fasting has also been shown by Dr Michael Mosley, author of “The Fast Diet” to improve blood glucose levels. One unexpected benefit of intermittent fasting is the effects on allergic diseases such as asthma and eczema (dermatitis) which affects about 10% of people in Europe and the US. Further studies have shown that in a test of 4 groups – people doing intermittent fasting, people doing intermittent fasting and moderate exercise, people just doing exercise and people doing nothing, that the people doing fasting plus exercise dropped the most weight and had the best improvement in cholesterol levels. Dr Mosley’s conclusions are:Our bodies respond to fasting in a way where they look to heal themselves as when they respond to stress and shock it makes them healthier and tougher. The scientific term is hormesis – what does not kill you will make you stronger.The benefits of fasting are:-· Weight loss· A reduction of IGF-1 (the reducing of risk of some age-related diseases like cancer)· The body repairs that begin because of fasting “stress”· A rest for the pancreas which improves insulin sensitivity and reduces risk of obesity, diabetes and heart disease.· Improved mood and mental well-being.References:”The Fast Diet: Lose weight, stay healthy ,live longer By: Dr Michael Mosley & Mimi Spencer.