If Luke and Nicole lose muscle on their plan, it will take them longer to get abs because more of the weight lost will not be fat.

Research from Dr. Eric Helms indicates that the optimal rate for fat loss while preserving muscle is about 0.5% to 1% of body weight per week.

To reach 20% body fat, Luke needed to lose approximately 20 pounds of pure fat.

Luke's initial body fat percentage was 29.2%.

Lack of sleep can double the time it takes to get abs.

Vicki lost 5 pounds in a month from only dieting and training her abs, but only 2 pounds were fat, with the rest being muscle loss.