Hi,
I just joined the forum and was skimming the martial arts section.

I am probably far from being considered an expert on martial arts (by any and especially by Japanese standards). That said, I was in a similar situation as you are right now 2 years ago. I am also a 1.9m tall guy and was a little "bigger" when I started martial arts back then. I'll share my story to give you a better picture on the selection process.

The first thing to sort out is what clubs available in your area. If you already live in Japan this may not be an issue, but if you live anywhere outside Japan ... the selection/availability drops down quite significantly. It probably begs the obvious, but do not plan to learn on any martial art by watching videos... always consider a reputable dojo or, if you are lucky, by personal instruction. Most of them will offer free trial classes, which helps a lot when making the right decision. Go with a Dojo that you are comfortable with and do not lock yourself into a specific martial art just because people told you it is good or appropriate for your case. If you do not like the people in the dojo or the style of instruction, the motivation will soon fade.

According to popular belief and several links you find on the internet, people attribute burning between 480 - 1200 calories per hour of Karate. In addition, I was originally looking for something that looked reasonably suitable for self-defense (but after doing it for 2 years your perspective will shift a bit)....

So my first choicen was Karate, specifically Goju Ryu. We train about 2.5h, 3-4 times a week. The session consists usually of a pretty rough warm-up of 20 minutes, followed by 20-30 of basics (punches, kicks, etc). During this time, you burn most of the calories from my perspective. Karate seems to exercise a variety of different regions of your body. When I was a newbie I used to feel sore in places that I did never expect to feel sore before .
The basics are followed by special topics. Our Sensei dedicates a lot of training sessions to Kata, its applications (bunkai), self-defense. Usually once a month they also throw in a sparring class (i.e. light-contact matches in a friendly and controlled environment), sparring also burns a lot of calories.

Since you are a tall guy, you can gain a lot of advantages by range in that particular sport.

Kata is an integral part of Karate that allows you to exercise your basics in a series of movements. Each of those moves has a specific application. Depending on the Karate style you will learn those applications in separate short exercises (bunkai) or sometimes as a streamlined 2-person-drill (rensoku). It usually takes a couple weeks until they teach you the applications, once they do you will realize the importance of Kata and don't find it boring anymore.

I would allege Jujitsu, Judo, Kenpo ... a similar exercise profile as Karate does.

The past 2 years in Karate helped me a lot to improve my fitness. Once you enter it can become quite addictive. When I was moved to advanced class about a year ago, I had some spare time to spend on other stuff and discovered Kendo as well. So in addition to Karate I joined a Kendo dojo and trained 3 times a week about 2h.

It is a very very different thing from Karate. I have to disagree with posters, who consider most martial arts to be somewhat similar in their exercise profile.
The entire sport is set up for competition and the progression appears to be (at least from my perception) quite slow. The warm-ups are a lot less intense than Karate and much more focused on arms, legs and feet.

For the first eight months, we did not get involved in any sparing but instead focused a lot on working out the basics. The most basic thing is movement, which is very constrained well defined for Kendo. The next thing they are going to teach you are basic hits. In Kendo the hits that score points are also well defined (and quite limited compared to other sword forms). Prepare to exercise those basics repetitively for months until the Sensei regards you capable enough to proceed to the next level.

From there they will teach you basic parter drills and at that point you will also be starting to wear the Kendo armor. They will also teach you the basic Kata at that point.

After that you will have partner drills that exercise spotting and hitting valid target areas. Beyond that they will allow you to engage in some basic sparring (and that is where I am right now after about 9 months of starting) .

In terms of exercise, Kendo seems to exercise the arms and shoulders a lot. As a beginner, it will take some time until you get the basic swings right. If you do them wrong you also end up having the occasional sore back (in addition to sore arms). Also having blisters on feet is quite frequent because of the sliding motion of the movements. Be prepared to take some tape to class to deal with them. Personally, I think Karate has the better exercise profile. Kendo is a fun sport if you are willing to put in the determination and time to get the basics right. Personally, if I were to choose my first martial art again I would start with something different than Kendo.

One issue that I faced when starting Kendo that may happen to anyone who starts with a weapons-form is perception. Friends, family or others may actually miss the point that you are doing it for self-improvement, character building (etc.) and see it as a negative. In their eyes this may go "beyond just self-defense" in a negative way. Being in Canada I know a lot of people from diverse backgrounds, including China. Some of them have a quite hostile opinion about Japanese sword forms for that matter (and historic reasons). I do not want to discourage you from Kendo or other weapons forms, but be prepared for this. This issue hit me out of nowhere (see my blog post about it for more thoughts) being aware of it may help you deal better with that, if it ever becomes an issue .

Apart from those two "groups" of martial arts there is lots of other stuff out there. I may give Kobudo or Battojutsu a try down the road. These ones are also very different from what was mentioned so far.

To conclude I would like to stress the importance of a good Dojo and instructor again. If you feel happy to do it and you practice regularly these guys become like a second family to you. In addition to training, you will probably also have the occasional "fun-night" out or visit seminars. At that point martial arts is not just about self-defense, character-building and focus anymore but it also becomes a very social part of your life.

Thomas

EDIT: links removed... just saw the spamming thread and noticed that links were not encouraged.