Karate isn't really cardio. It's a strange type of strength training that focuses a lot on muscle stamina.
No doubt will you gain muscle doing karate. You might even grow a bit more, it's a great type of exercise to get into. However your muscles will not be bulky and huge, they'll be slender, carved, and hard as hell.
It's true, weight only means something when you're measuring extreme ends of the spectrum. Muscle is much smaller and compact than fat. It's also heavier than fat. You can be perfectly thin, but if you've got a high amount of muscle that isn't built outwards to bulge, you may very well weigh a lot more than you look.
As far as your diet is concerned, obviously you need to eat properly to lose weight. Also remember though, your organs burn calories as they function, even your stomach. Each time you eat something and kick in the digestion process, you're forcing your digestion to exercise a little harder to get that food starting to break down. Free burned calories, just by getting your digestion to start up more times a day.
Now this is also purely personal opinion, but many people are advising you to eat more meat. Personally I'd advise losing some meat, and gaining a LOT more plantation and nuts to make up for it.
Meat is heavy, it takes a lot of time to digest for quite a few calories and a huge amount of nutrience. Great, but, you've spent all that time digesting a single piece of food full of nutrience which have already been processed by an animal out of the plants. Yup, there's a difference between some plant and animal derived nutrition. When you eat plants, your body has to take what's in the plants and alter it to make it useable in an animal body. Eating it from animals, that work's already done for you pretty much. There are differences between eating plants and animals, and I really think there's a lack of consideration given towards the differences between plant and animal nutrition.
It does seem that vegetarians have generally better body odour, immune system, sense of taste and smell, eyesight, oral health, in many cases organ function and digestion, and well, any released fluids tend to possess both a better odour and ummm... taste, according to that old woman who talks about sex on tv all the time. There are of course advantages to eating meat as well, so I don't advise against it. I mean, it's good for us, we have the teeth for it, so we might as well. I'm just saying, if you're eating the meat for the nutrition, there are other ways to get it that would come with plenty of advantages because I assume living in this age you already eat plenty of meat.
