Optimum nutrition serious mass choc peanut butte 5450 g serious weight gain requires serious calories however those who need the extra calories most often have the toughest time consuming enough of them for many aspiring to be bigger a highly active metabolism weaker appetite and on the run lifestyle can make consuming enough calories through whole foods alone with serious mass youve got nothing to lose and lots to gain weve consolidated over 1 270 calories 50 grams of protein 249 gr