It is important to note that after any type of weight loss you will likely have a lower resting metabolism. This is partially due to having a lower body mass, requiring less calories to maintain. And sometimes due to adaptive thermogenesis, meaning you will need to eat less calories per day to maintain your weight compared to a similar individual at the exact same weight who has never been on a diet (28). But the effects of adaptive thermogenesis are typically short lived, and for most the difference could be as little as a 5% decrease in BMR. However, after crash dieting, your BMR could drop 10 to 15%, which could have a significant impact on your TDEE and weight maintenance efforts (29,30,31). 
While toning your muscles is best achieved through exercise, ditching the fat that’s obscuring them starts in the kitchen. Luckily, one easy way to get the ball rolling on fat loss outside the gym is a habit you probably already have: drinking coffee. Research published in the American Journal of Clinical Nutrition reveals that obese study subjects whose diet was supplemented with caffeinated coffee significantly increased their metabolic rate, and subjects of an average weight shed more pounds, too.