That's an interesting problem. I'll assume you want to gain muscle, not just get bigger any way you can? If that is the case, sure, you need to increase your calorie intake, at least that is the scientific gospel. However, in my personal experience, I have found shoving calories down my throat to be a royal pain.
When I starting eating as healthy as possible, increasing my calories with ONLY quality food, and not by much more than 300-500 calories a day, if at all, I gained muscle and felt strong and energized.
It will take time to gain 20 pounds; months or years, depending on where you are starting from, your age, etc. But always work with compound movements, and keep healthy food on hand. Most experts will say 'eat several small meals a day,' but you may get results eating only twice a day. Experiment and see what feels better.
One more thing, 5000 kcal a day for a 140 lb. male is ridiculous. Find a good calorie calculator (you can find a good one at Scoobysworkshop.com) and you can determine exactly how many calories you should be eating.
Hope this helps, Cheers.