These pick-me-up snacks dissolve in our stomachs quickly, where they're converted into glucose. This races into our bloodstream, flooding our bodies with energising sugar. But these highs are over quickly - our bodies overproduce insulin to combat the sugar rush, which sends our energy levels crashing. This doesn't just leave us hungrier: it's also linked to heart disease, diabetes and obesity.

 

Modern diets are packed with blood-sugar-raising foods - chips, bread, cakes. They lower "good cholesterol" levels and raise triglycerides, fats that cause heart disease. In a Cambridge University study of 10,232 middle-aged people, those eating blood-sugar-raising foods were 22% more likely to develop heart disease.

 

Over time, the profusion of insulin our bodies produce to lower sugar levels damages our insulin receptors, making them less effective. This "insulin resistance" is a step closer to diabetes and can lead to cancer, weight gain and even affect the brain.

 

But eating the right foods can balance blood-sugar levels. The glycaemic index (GI) and glycaemic load (GL), which gauge the best and worst foods for blood sugar, reveal some unexpected foods that can transform your health. Most carbs are blood-sugar enemies so try making three of your day's carb servings whole grains – studies show that this cuts your heart-attack risk by 52%. They're found in brown rice, popcorn and oatcakes. It's not all about carbs, though - protein takes longer to break down, so blood-sugar levels aren't sent soaring.