Some people want to lost weight and some other want to gain mass and transition to heavier weight category. So one person wants to speed up metabolism and burn extra calories while the other wants to convert it into more mass, preferably muscles. To make this process faster and easier you should consider taking some quality supplements.
Creatine is one of the safest sports supplements: it doesn't have any side effects and you practically cannot overdose it. It increases your endurance so you train longer without feeling tired which translates into better gains from a single workout session. Creatine is also proven to increase your strength and to accelerate the growing of muscle fiber. It should be on the top of your list of supplements if you are serious about accelerating your training.
A food rich in creatine is red meat, especially beef, and fish. To be able to get 5g of creatine from a food you would have to eat around one pound/0.5 kg of beef every day which may be problematic and quite expensive. That's where supplements come in handy.
According to some studies, ethyl ester creatine has a better absorption rate than creatine monohydrate, while some other sources claimed that there is no difference. I have tested both types - and also a few different brands - of creatine for a long period of time on myself and I haven't noticed any difference. What I also observed is that a pure monohydrate allowed me to train longer without feeling exhausted than ethyl ester. Guys I've been training with have a similar opinion so I recommend creatine monohydrate over ethyl ester for a regular training.
OK, I know that fat is not a supplement but it is very important in your diet so that everything else works as it should. Simply put, your body needs fat to absorb proteins to build muscles. To be clear I'm not saying that you should consume ANY type of fat but a good quality fat: virgin olive oil, avocados and various types of nuts and seeds (like peanuts, walnuts, hazelnuts, sesame seeds etc) and...butter, yes a real butter - in a limited amount - is good for you, much better than vegetable oil spreads. You can find more information about balanced diet and proper nutrition for fighters under this link: Muay Thai diet.
The equation is simple: the more your train and sweat the more minerals and microelements your body needs to replace.