GNC Pro Performance Bulk 1340, as the name suggests, contains1340 calories, which is the highest in the market. It is formulatedwith a nutrient-dense composition of Protein and Carbs in theperfect ratio of 1:7, which not just serves as a rich source ofcalories but also a healthy one to ensure your body bulks upcorrectly without unwanted flabs. Proteins and Carbs play a major role in mass gainers. The maindifference between the two is the Protein to Carbs ratio. GNC ProPerformance Weight Gainer features Protein 1:4 Carbs ratio while Bulk1340 features Protein 1:7 Carbs ratio with comparatively more carbs andresultant higher calories.