The new Mars Protein Bar is just 200 calories and has the nutritional profile you would expect from a leading Protein Bar but with all the great taste of your favourite confectionery brand. ?It tastes like a Mars Bar?. The Mars Protein Bar contains 19g of protein combined with soft caramel and chocolate. The individually wrapped Mars Protein Bars can be easily slipped into any gym bag as a post work out snack. Protein Bars have been taking to a new level with the tasty Mars Protein Bar.