Slimming down with intermittent fasting: pros and cons of the Fast Diet
They call it the "FastDiet," and for those who know English it may mean that it is a diet for losing weight fast. But "fast" does not only mean "fast"; "fast" also means "fasting." And it is precisely intermittent fasting-that is, practiced only on certain days-that proposed by the creator of this dietary regimen (BBC physician and popularizer Michael Mosley) not only to lose weight but also to protect health by keeping risk factors such as blood pressure and blood cholesterol under control.
But how exactly does it work? What is the evidence for its effectiveness? And can it compete or at least offer itself as an ally in the fight against cardiovascular problems with other approaches already widely used to protect heart and artery health, such as taking Omega-3s of marine origin?
Let us proceed in order, first explaining what this dietary regimen consists of.
Fasting 2 out of 5 days
The Fast Diet involves drastically reducing the amount of food eaten for only 2 days a week; that's why you might hear it referred to as the 5:2 Diet, where 5 are the days when you can eat freely and 2 are the days when you need to practice fasting-or, better yet, eat much less than your needs would predict.
In particular, on fasting days one should limit oneself to consuming 500 Calories if one is a woman and 600 Calories if one is a man, an amount equal to about a quarter of the average requirement of an adult individual. The foods to be preferred on these days are those rich in protein (such as fish and meat) and fiber (especially vegetables) endowed with greater satiating power; on the other hand, it would be good to avoid those rich in carbohydrates (such as pasta, rice and potatoes), especially if they are refined (such as 00 flour). It is also better not to drink alcohol, while milk, coffee and tea are allowed without any problems.
On the other hand, during the other 5 days of the week you are free to meet your caloric needs, to be calculated individually based on your weight, height, age and daily physical activity.
The days on which one decides to fast can be freely chosen. Beware, however: intermittent fasting is not for everyone. In addition to those who are underweight, Mosley also advises against it in cases of:
- Age under 18 years,
- Eating disorders,
- Type 1 or taking diabetes medications other than metformin,
- Pregnancy or breastfeeding,
- surgical interventions,
- malaise or fever,
- Severe psychological/psychiatric disorders,
- Taking warfarin.
In addition, Mosley also recommends that you consult your doctor if you are taking other medications and are concerned that intermittent fasting may interfere with their effect and if you have significant health problems.
The effectiveness and side effects of intermittent fasting?
Our advice is to always consult a doctor or nutritionist before you go on a diet, so that you can be sure that you are always providing your body with what it needs and not getting trapped in false food myths that could lead you to make not only unnecessary but sometimes even potentially dangerous sacrifices.
As for intermittent fasting, according to Mosley, the main side effects are severe hunger (especially at the beginning of the diet), insomnia, headaches, and constipation. Over time, then, intermittent fasting would become an easy habit to follow, and once weight loss goals were achieved, one could switch to fasting only 1 day a week.
But can you really lose weight? Studies conducted to date seem to confirm this. As for cardiovascular benefits, on the other hand, there are still few studies conducted on humans; however, it seems that intermittent fasting can help reduce C-reactive protein (a marker of inflammation), total and "bad" cholesterol, blood pressure, and even triglycerides (the same ones that are lowered by Omega-3s).
However, experts seem to be in no doubt that more research will have to be conducted before they can say the final word on whether this approach is really effective.
Sources:
Horne BD et al. Health effects of intermittent fasting: hormesis or harm? A systematic review. Am J Clin Nutr. 2015 Aug;102(2):464-70. doi: 10.3945/ajcn.115.109553
Stockman MC et al. Intermittent Fasting: Is the Wait Worth the Weight? Curr Obes Rep. 2018 Jun;7(2):172-185. doi: 10.1007/s13679-018-0308-9
The 5:2 fast diet. thefastdiet.co.uk. 02/07/18
