Agave, aspartame, saccharin and stevia have all become popular in the last few years, but scientific evidence produces mixed results when it comes to the effect these substitutes have on the body. These alternatives are much sweeter than sugar, so the theory is that you can have less of it for the same sugary hit — and so everyone wins, right? Wrong.
Agave is as calorific as honey, and has no added health benefits.
Aspartame has a worryingly long list of side effects including nausea, numbness in extremities and heart palpitations. It's most commonly found in diet soft drinks.
Saccharin was linked to cancer of the bladder for a long time, but scientists have disproved the theory. Pregnant women and children should keep away from this sweetener, which can be found in some chewing gum, jams and baked goods.
Stevia is the more desirable sugar substitute on this list, but it's far from perfect. It's all natural and about 300 times sweeter than sugar — just make sure you use the pure stuff, not processed.