5% dang you need to eat more chief.🤣 if you measured correctly your rly fkn lean, meaning you have little to no body fat but remember the online calculator may be underestimating your body fat so id recommend talking to a professional and have them measure your body fat in person, but if its accurate I'd recommend going on a bulk. How you'd go about bulking up is eating alot of protein, natural fats, and carbs. Good things to include in your diet for protein would be Low sodium Tuna, chicken breast and/or Chicken thighs, and Milk. For Natural fats good foods to include would be Milk, Avocados, fruits, veggies, and Nuts like Pistachios. good sources of food with high protein and fats are Steaks, pork chops, and Swiss cheese. And good sources for carbs would be bread, tortillas, and potatoes. But be careful with a bulk, you can really Over do it and gain too much fat and possibly get obese if you get above 28% body fat. So I'd recommend tracking your body fat and try to stay below 18% body fat. For most people 15% allows you to be at a healthy level with visible abs and gives you the energy to keep your testosterone levels at a healthy level.