You Sleep, you win!
Researchers suggest how much sleep and the quality of sleep we get is actually directly related to hormones that can influence our weight. Leptin and Ghrelin work together to control the appetite and feelings of fullness. So what's the connection? When we don't get enough sleep, Leptin levels decrease, therefore leaving us not feeling satiated. Not enough sleep can actually cause Ghrelin levels to increase, which then stimulates our appetite. The combination of the two can lead to overeating, which can lead to being overweight.

The keys to having  six pack abs and keeping them are:

Cardiovascular: Need to get the cardio in on a consistent basis. Three-Four times a week at 20 minute sessions of intense (80% Max Heart Rate) cardio will get that extra layer of fat off. 

Clean Eating: Your meals should be divided into 50% Protein, 30% carbs, 20% fat. EAT ACTUAL FOOD! Try not to eat too much processed foods or snacks. Eat 6 small meals a day and 8 glasses of water. 
Abdominal Exercises: Working the entire core (not just crunches) has way more effect on the stomach area. Planks, Side Planks, abdominal twist, are just some of hundreds of core exercises to get you the six pack you always wanted!