YOU are slumped over your computer keyboard and the 3pm demon taps on your shoulder, whispering sweet sugary and salty nothings. Chocolate! Chippies! Cappuccino! Then come the cravings and you are caught in a moment of weakness. The vending machine may be in sight, but unless it's offering raw nuts and freshly chopped vegetables, it's time to look elsewhere.
That is because the high you get from a sugary snack is likely to be short-lived.
The glycaemic index gives foods a rating based on their effect on the blood. Numbers are assigned to different foods: those less than 55 are classed as low GI, and these cause blood glucose levels to rise slower than their high-GI counterparts.
If you have ever experienced a ''sugar high'', it's likely you were munching on snacks awarded a larger number on the GI scale. Big numbers are a big no-no if you want sustained energy to keep you going in the afternoon.
The Glycemic Index Foundation recommends you ''keep it handy'' when it comes to low-GI snacks. Things such as fresh and dried fruit, trail mix and low fat natural yoghurt get the tick of approval for snacking on. Breakfast is all important when it comes to setting the tone for your day.
Incorporate grains and low-fat proteins instead of sugary cereals and white bread: if your blood glucose levels spike after breakfast, that demon could arrive early and tempt you mid-morning.
Some foods are now labelled with GI information, but if in doubt, check out the Glycemic Index and GI Database website: glycemicindex.com