Intermittent fasting and chronic illness: Everything you need to know!

What is intermittent fasting?

Fasting means voluntarily depriving oneself of food. It is an ancestral practice often carried out for religious or spiritual reasons, but also for therapeutic purposes. It is even becoming a fad!

Intermittent fasting involves reducing one's food intake window, or eating as much as one normally does but over a shorter period of time. In other words, it includes eliminating either breakfast or dinner and eating the equivalent of the skipped meal during the rest of the day. Intermittent fasting can also entail reducing one's caloric intake, including full-fast days and "normal" days.

Intermittent fasting must therefore be distinguished from complete fasting (zero calorie intake) and continuous partial fasting (continuous restriction of calorie intake). This type of fasting can be practised by a healthy person (more for preventative purposes) or by a sick person (more for a curative/therapeutic purposes).

Different types of intermittent fasting

We can distinguish several types of intermittent fasts, such as:

• The 16/8 method: which involves fasting for 16 hours out of 24, something which is much more common than we think, as many people skip breakfast!
  
  
• The 5:2 method: where one consumes 500 calories per day, on two non-consecutive days per week.

These two methods are intended for occasional practice - by individuals who are not used to skipping meals - to rest the digestive system.

• Fasting every other day, or 1 day once or twice a week.
  
  
• Therapeutic fasting (sanogenesis): a method that must be supervised by a physician and practised for therapeutic reasons (cancer, chronic inflammatory illnesses, etc.).
  
  
• Fasting when you want/can: depending on how hungry you feel, this is the most intuitive method.

Benefits of intermittent fasting

Intermittent fasting appears to have an effect on circadian rhythm, gut biome, and caloric restriction. Regarding its effect on the gut biome, this regimen seems to reduce the discomfort associated with problems of intestinal permeability and inflammation often present in obese persons, in particular.

Many people observe weight loss following their intermittent fasting regime because, if it is well practised, the metabolism adapts to food restriction by drawing from lipid stores once food reserves have been exhausted.

Other beneficial effects can be noted, such as a decrease in hunger, improved sleep, or an increase in vitality and concentration.

Is it clinically approved?

9 interventional studies studying the effect of intermittent fasting over several months in overweight or obese patients have been conducted. Of these, 7 confirmed weight loss and about half showed an improvement in metabolic markers. However, metabolic markers were not always improved in the various studies. There is fairly clear evidence that intermittent fasting is more beneficial than total abstinence from food and some restrictive diets. Scientific studies conducted in mice have shown good results on increased lifespan, resistance to oxidative stress, and toxicity with chemotherapy.

Caution! It is important to note that studies on intermittent fasting are not always of high quality or are well-controlled, and often show limited evidence.

For which diseases is it recommended?

Intermittent fasting could improve symptoms in Irritable Bowel Syndrome, improve pain and morning stiffness in rheumatoid arthritis, significantly reduce pain in chronic pain conditions such as fibromyalgia. In metabolic syndromes such as diabetes, metabolic fasting could increase insulin sensitivity, stimulate lipolysis and lower blood pressure. It could also improve the signs of atopic dermatitis.

Fasting for cancer

Fasting (generally speaking) is under development in oncology: it could improve the impact of cancer cell treatments, protect healthy cells, reduce the side effects of chemotherapy such as nausea/vomiting, diarrhea and abdominal cramps, and rebuild the immune and hematopoietic (which forms cellular blood components) systems more quickly.

Fasting for cardiovascular disease

Improvements in lipid metabolism, inflammatory markers, and high blood pressure have been observed, and decrease in weight and in blood glucose parameters have been noted.

Other diets such as the Fast Mimicking diet may be recommended in Crohn's disease cases. This diet involves consuming plant-base, whole-food derived prepackaged meal kits which are low in calories (restricting daily calorie intake) and rich in good fats for 5 days.

However, there is no scientifically substantiated and proven conclusion to validate these medical indications. In chronically ill patients, it is vital to seek medical advice before starting an intermittent fast, which must be accompanied by appropriate medical supervision, in a fasting clinic, for example.

For whom is it contraindicated?

Intermittent fasting is contraindicated in children, pregnant or breastfeeding women, the elderly, and those at risk of hypoglycemia or with hormonal imbalances..

Some advice before starting intermittent fasting

• Stay hydrated by drinking a minimum of 2 to 2.5 litres of water per day.
• Maintain adequate protein intakes (around 1.2 g of protein/kg/day).
• Consume high-quality fats, especially vegetable fats, between fasting periods.

If you don't know what type of fasting is right for you or how to go about it, it is best to consult a healthcare professional before beginning a fast.

Do you practice intermittent fasting? Have you noticed an improvement in your health?