A few days ago I went into Waterstones looking for a novel and instead came out with a glossy, cheery book entitled "I Quit Sugar for Life". Contrary to what you might be thinking, it was actually a treat to flip through pages of tantalising recipes. However, the author Sarah Wilson hasn't just given the reader pretty pictures, she is also spot on with her science.

Sugar is addictive and its deleterious effects target more than just your waistline. In fact, avoiding the office biscuits or that slice of afternoon cake isn't just a matter of willpower. Sugar meets the four criteria necessary to qualify as a drug: bingeing, withdrawal, craving and sensitisation.

Because diet is so strongly linked to mental wellbeing, I almost always ask clients about what they eat, as well as how often they eat. If you struggle with anxiety, then allowing your blood sugar levels to drop is one of the quickest roads to a panic attack and certainly one of the best ways to destroy your focus.

Caffeine, sugar, simple carbohydrates and large gaps between meals can all cause blood sugar levels to drop rapidly. As our brains require a constant supply of blood glucose, this situation is interpreted as a crisis. Adrenaline and cortisol are released into the bloodstream, thereby inducing symptoms such as rapid heartbeat, shallow breathing, trembling, nervousness, lack of concentration and eventually, panic.

So if, for whatever reason, you’re already feeling the afternoon jitters, think twice before reaching for the biscuit tin. If you want to feel calm and confident for the rest of the day, try a snack dense in protein, fibre, or good fats such as hummus and oat cakes, apples with peanut butter, Bounce Coconut Protein Balls, or smoked salmon or avocado on buckwheat crackers. If you can find a little time to make your own treats, Sarah Wilson’s gems also include pumpkin and chia muffins and sugar free salted peanut butter fudge. Now there’s a boost you can really use.