Lose Weight With Intermittent Fasting: Pros and Cons of the Fast Diet

It is called the “Fast Diet,” and for those who know English, it might mean a diet to lose weight quickly. But “fast” does not only mean “quick”; “fast” also means “to fast.” And it is precisely an intermittent fasting – practiced, that is, only on certain days – that is proposed by the creator of this dietary regimen (the doctor and BBC presenter Michael Mosley) not only to lose weight but also to protect health by keeping risk factors like blood pressure and cholesterol under control.

But how exactly does it work? What evidence supports its effectiveness? And can it compete or at least be proposed as an ally in the fight against cardiovascular problems alongside other widely used approaches to protect heart and artery health, such as the intake of marine-sourced Omega-3s?

Let’s proceed step by step, first explaining what this dietary regimen consists of.

Fasting 2 days out of 5

The Fast Diet involves drastically reducing the amount of food consumed only 2 days a week; for this reason, you might hear it called the 5:2 Diet, where 5 are the days when you can eat freely and 2 are the days when you must fast – or rather, eat much less than your usual needs.

Specifically, on fasting days, you must limit yourself to 500 calories if you are a woman and 600 calories if you are a man, amounts equal to about one-quarter of the average adult’s needs. The foods to favor on these days are those rich in protein (such as fish and meat) and fiber (especially vegetables), which have a greater satiating power; it is better to avoid foods rich in carbohydrates (such as pasta, rice, and potatoes), especially if refined (such as white flour). It is also better not to drink alcohol, while milk, coffee, and tea are allowed without problems.

During the other 5 days of the week, you are free to satisfy your caloric needs, calculated individually based on weight, height, age, and daily physical activity.

You can freely choose which days to fast. However, be careful: intermittent fasting is not for everyone. Besides those who are underweight, Mosley also advises against it in cases of:

• age under 18 years,
• eating disorders,
• type 1 diabetes or use of diabetes medications other than metformin,
• pregnancy or breastfeeding,
• surgical interventions,
• illness or fever,
• serious psychological/psychiatric disorders,
• use of warfarin.

Furthermore, Mosley recommends consulting your doctor if you are taking other medications and fear that intermittent fasting might interfere with their effect or if you have significant health problems.

Effectiveness and side effects of intermittent fasting?

Our advice is always to consult a doctor or nutritionist before starting a diet, so you can be sure to always provide your body with what it needs and avoid falling into false dietary myths that could lead to not only useless but sometimes potentially dangerous sacrifices.

Regarding intermittent fasting, according to Mosley the main side effects are intense hunger (especially at the beginning of the diet), insomnia, headaches, and constipation. Over time, intermittent fasting would become an easy habit to follow, and once weight loss goals are reached, fasting could be reduced to only 1 day a week.

But can you really lose weight? Studies conducted so far seem to confirm this. As for cardiovascular benefits, studies conducted on humans are still few; however, intermittent fasting seems to help reduce C-reactive protein (an inflammation marker), total cholesterol and “bad” cholesterol, blood pressure, and also triglycerides (the same that are lowered by Omega-3s).

Experts, however, seem to have no doubts: before the final word on the real effectiveness of this approach can be given, further research must be conducted.

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