In contrast, others continue to emphasise their importance at the base of the food pyramid and state that they are crucial for our mood, general health and even cognitive performance. The truth perhaps is that no one size fits all.

Carbs come in a large variety of foods such as fruits, vegetables, grains, legumes, and tubers, the body converting them into sugar to provide energy. When on a low carb diet, the liver releases ketone bodies to provide energy to the body and the brain. The conversion of fats and proteins into ketones is an energy-intense process. Some people feel more energised and alert when consuming fats and proteins to fuel their brain and body, whereas others lean toward carbs as their primary source. For those in the former category, one hypothesis is that the transformation of fats and proteins into energy is hard and forces the adrenal glands to work overtime.

Effectively, the brain enters into a starvation mode while the cortisol, the hormone involved in the body’s reaction to fight or flight, increases. As the cortisol is released, the ability to respond to stress is affected and the mood compromised. According to a randomised controlled trial, stress-prone individuals saw a drop in their cortisol level and a reduction in their depressive mood by adopting a carb-rich and low-protein diet.

According to the latest scientific research, the connection between the gut and the brain is very strong! The diet of an individual affects the composition of the microbiota, the gut environment. In turn, the gut bacteria sends information to the brain through the vagus nerve. This means a diet high in processed and refined food can contribute to the creation of unhealthy intestinal flora. Due to the strong gut-brain connection, unhealthy intestinal flora can impact brain health and increase the risk of developing anxiety, depression or other issues. One way to normalise the mood and keep the brain performing at its optimal level is to maintain a healthy intestinal flora. Eating fermented food is perhaps the best and most natural way to achieve this goal.

Fermentation is the process used to make wine, yoghurt, bread and other products. Microorganisms including yeast and bacteria, consume the carbs found in food. The longer the fermentation time, the greater the number of carbs eaten by the microorganism, and generally the increased sourness of the food itself.

A particular gut bacteria called Lactobacillus rahmnosus, which occurs naturally in some fermented food such as Parmigiano Reggiano, can dramatically increase the production of one of the crucial neurotransmitters responsible for calming the activity of the brain, GABA. What a great excuse to indulge on this delicious Italian cheese! Another example is the “mother yeast”, a real live organism that not only “eats” the sugar of the dough, but also “breathes” in the open air.

If you find you are irritable and brought easily to tears on a low carb regime, maybe before reaching for medicine, grab some high quality fermented food such as yoghurt, a piece of Parmigiano Reggiano, a slice of a good quality sourdough bread or some focaccia.