Retailers can cash in on the protein trend as Grenade expands its Carb Killa range with Chocolate Fudge Brownie.

The product is available to conveneince stores now and has an RRP of £2.49. The new bar contains two grams of sugar per bar, and 15 grams of whey protein.

The brownie contains walnuts and chocolate chips and a milk chocolate layer and fondant topping.