Can a maltitol-sweetened protein bar work in a keto diet?

Keto diets are an interesting and trendy way to help weight loss. By restricting your carbohydrate intake, the body is forced to enter “ketosis,” a metabolic state in which, in the absence of carbs, it instead burns fat for energy.

Sugar alcohol, maltitol (E965) is widely used to reduce the sugar levels of many protein snacks without adversely affecting the product's level of sweetness. But whilst the sugar levels drop, maltitol still contains carbs. A lot of carbs. Sugar has a carb level of 100g per 100g, so it's 100% carbs. Maltitol has a typical carb level of 99.8%, but its level of sweetness is a little less than sucrose, so in theory, you need about 10% more in order to achieve the same level of sweetness in your food.

So, based on the carbohydrate level alone, maltitol might actually be a worse way to sweeten your protein snacks than sucrose if you want to eat this as part of your keto diet.

But dig a bit deeper, compare the absorption rates and the story is a bit different.

Sucrose is highly absorbable in the human digestive system. All of it will be absorbed by the time the food leaves the small intestine. Sugar alcohols like maltitol and much harder for the body to absorb, so much of it can pass through into the colon without being absorbed before it is excreted.

In addition, the energy levels of maltitol are 240kcal per 100g compared to 400kcal for sucrose. This means that a protein bar with the same level of sweetness using maltitol will have a much lower energy level than one sweetened with sucrose and therefore be much more suited to a weight loss diet.

On balance, I think that replacing sugar with maltitol is a sound way to sweeten your protein bar and as long as the protein level is not too high, it can fit into your keto diet.