I've vaguely described what a paleo diet is. What I haven't gone over are the arguments for adopting it.

First, the facts. Humans have only had agriculture for the last ten or twelve thousand years. Before that all humans were hunter gatherers and had been for hundreds of thousands of years. We hunted (actually, early humans hunted all the large mammals on earth into extinction), gathered vegetables and fruits and grasses and nuts and eggs that grew wild. No cultivated grains - what we know as wheat didn't exist until early farmers cultivated crops for a long while and bred grasses that provided more food.

None of this so far is controversial. A few morons out there think our paleolithic ancestors were vegetarian, but there's just no way to support a human body by foraging on vegetables alone. Primates that don't eat meat have to eat all day long. They have bigger stomachs, smaller brains, and can digest a lot of plants that we can't digest. The only way to support a large, calorie hungry brain is by eating meat.

By the way, lots of groups of people maintained this hunter gatherer lifestyle until very recently, and a few groups still do it in very isolated areas.

Now, what happened when these people started growing crops instead of hunting for their food? Well, they got sicker. Their kids were shorter, had crooked teeth, and developed all kinds of debilitating diseases that had never occurred before. We can tell this by looking at and comparing the remains of early agricultural people to their hunter gatherer ancestors. Those easy to grow grains have too many carbohydrates, too many anti-nutrients (substances that bind to and leach nutrients out of your body), too little protein, and too few other nutrients to support healthy humans.

So why did they stick to it? It's all about population density. Once you have enough people in a given area, say a valley, it's a lot easier to feed them all reliably with agriculture than through foraging. And if your neighbors are foraging and you're growing food, you can support more kids, even if their teeth are crooked and they get arthritis when they age. More kids means more fighters, and pretty soon your neighbors are growing their own crops to keep you from killing the males and stealing their women. Agriculture gives an advantage to your group, and pretty soon every group of humans who weren't isolated had to start doing it. They also domesticated animals, which helps you get your farm work done, and so we got civilization.

The crux of the problem is that we were well adapted to being hunter gatherers. What does that mean? It means all humans had a complement of genes that made them healthy on a hunter gatherer diet. Over a couple of million years any humans who couldn't, for example, tolerate meat well, would have either died before passing on their genes or just had problems breeding (they would have been less healthy, and have attracted fewer mating opportunities). Remember, these people lived in a harsh, violent environment. Nobody was going to put perennially sick members of their tribe (members who couldn't tolerate their diet) into hospitals or nurse them for decades and certainly nobody was going to bear their children. Over hundreds of thousands of years of not being passed on, non-meat-friendly genes would have disappeared from the gene pool.

Back to the farmers. Once humans started farming and raising animals, a new set of genes was going to be advantageous. For example, suppose some kid is born with a mutation that allows him to digest lactose as an adult. If that kid is born into a hunter gatherer society, there's no particular benefit for that kid - nobody has access to milk, so that kid wouldn't come across as a good catch or anything. Now suppose that same kid is born into a group of farmers that has some cows around. The kids drink milk, but the adults can't handle it. Except for the mutant, who keeps on drinking milk, because he can (remember, he's got the gene that lets him). No big deal until, maybe one year the crops fail. All the other males are starving, but this one guy is healthy and strong from drinking milk. Who do you think is going to get laid more often (excuse my vulgar way of putting it)? After a few generations you have a population that can tolerate milk better than their ancestors.

In fact, you can see this - lactose intolerance is prevalent among groups that didn't domesticate cows, while those that domesticated cows early (relatively speaking) have much less lactose intolerance. It takes time, though, for these changes to occur - many thousands of years - because you have to wait for the right mutation to occur, then spread, etc.

Suppose some alternate world where humans lived on grains and dairy for a million years. I'd guess that we'd be well adapted to, and live healthily on, those grains. Someone somewhere would have gotten a mutant gene that lets them expel or neutralize phytic acid, and they would have had stronger, straighter teeth, and in ten thousand years all humans would have that gene. Someone somewhere would have gotten the set of mutations that allows their immune system to handle milk proteins and passed it on.

But it hasn't been a million years. I'ts been ten thousand, and while we've partially adapted to the agricultural diet, we haven't fully adapted. How do I know? There's lot of evidence that grain and dairy cause all kind of health problems that we don't get from meat, fruits and vegetables, and seeds and nuts.

Does that mean anything modern is bad to eat? I'm going to say not necessarily. Take tea, for example, Did paleolithic humans drink tea? I don't think so (I could be wrong, though.) Does that in itself make tea bad? Well, it might be that tea has nothing in it that is particularly bad for you, despite the fact that we didn't evolve to be tea drinkers.

The facts about our evolution, though, should give us an idea of what to look out for - of what we should be suspicious. If our paleolithic ancestors ate it, then we're adapted to it. If they didn't then we should be SUSPICIOUS - we should look at the research and see if it's okay or not.

I'm guessing that grains and dairy act as sort of low level allergens for a lot of people. I don't get an asthma attack from eating a bagel, but eating bagels might make the asthma attacks I do get, triggered by other allergens, more severe. I'm hoping that taking grains and dairy out of my diet for a few weeks or months will give me more energy by relieving some of my allergy symptoms.

What makes me think that this might work? Two things. First, it makes evolutionary sense that I wouldn't be well adapted to the proteins in grain and dairy. Second, there's lots of anecdotal evidence that people who take grains and dairy out of their diet feel better - more alert, less tired, etc. Anecdotal evidence is NOT PROOF. I'm not sure about this. I have just enough evidence to think it might be true and try the diet out.

I'll let you know if it works.

Osu.

I mentioned the paleo diet yesterday without going into any details about it. If you're familiar with the diet, skip this post (and probably the next two or three!) If not, here's a brief introduction.

With any diet plan you have to consider two different things - what is it, and why should one follow it. Once you've decided to follow a plan there are other things you'd be interested in, like recipes and tips for cooking and eating out and so forth, but that's for later. I'd rather not try to address both questions in one post, so I'm going to start with an overview of what paleo eating is, and save the justification (why some people think it is a good eating plan) for another post.

There is not any one paleo diet. When I say paleo I mean a diet similar in substance to the diets proposed in the books "The Paleo Diet" and "Neanderthin," various websites like the Caveman Forum and Catalyst Athletics, Art De Vany's site, and a few other places. These diets all recommend that we eat more like our paleolithic ancestors - and I don't mean their table manners, I mean eat the foods that were available to our stone age ancestors and only those foods.

If you're not an anthropologist you might wonder what those foods are. Basically, we're talking about avoiding any food that was developed after the advent of agriculture. Stick to what hunter gatherers ate. Lots of meat, fresh vegetables, some nuts, some eggs, fruit. Eat more of the meat - organ meats, the heart, etc. What can't you eat? Grain (any grain), potatoes, legumes (beans), and dairy (you can't milk a wild animal). So no bread, pasta, peanuts (they're legumes), etc. No cheese, milk, butter. No artificial stuff - no nitrates, preservatives, no vitamins, no modern crap.

Why? I'll explain that another day.

Not all paleo diets are identical. I think all of them advise staying away from grains and beans. Some add nightshades to the prohibited list (tomatoes, peppers). Some allow dairy, some not. Some advocate eating all or most of these foods raw. Some allow limited quantities of alcohol (wine, beer) but some don't.

A few big issues are as follows. Different adherents have different beliefs about saturated fat. So some advocate cooking in canola oil, some in coconut oil (the latter is mostly saturated fat, which I think is fine, but many disagree). As I mentioned, a big issue is whether dairy is allowed and how much. Clearly dairy is not paleolithic, but for some dieters that's okay. Coffee and tea are other questionable substances - not paleolithic, but may be okay, may not, depending on your slant.

Meat is good (in fact, necessary). Some advocate trimming the fat, others advocate eating all of the good stuff (our stone age ancestors definitely ate the fattiest parts of the meat). One issue with beef fat is that our paleolithic ancestors ate animals that were grazing in the wild. The animals they hunted weren't cooped up and fed grain all their lives. When animals eat grain the kinds of fats they store in their flesh are different than when they eat grass. Grass fed animals have much higher levels of Omega 3 fatty acids and other healthy fats. Going to town on regular store bought meat may or may not be healthy but it isn't really what our paleolithic ancestors did. On the other hand, eating grass fed beef (which can be bought online and ISN'T the same as organic beef) is very similar to what our ancestors ate.

Different advocates stress fruit to different extents - everyone allows it, some advocate limited it. Dried fruit (fruit you dry yourself, without adding preservatives and sugar) is good, as is jerky, but storebought dried fruit and jerky might have stuff in it you don't want to eat.

Summary: meat, lots of veggies, some fruit and nuts. Maybe dairy, maybe limited alcohol, maybe limited artifical stuff like sweeteners.

What will I be doing? I can't be superstrict. I'll still be eating small amounts of cheese (I can't do veggies without some salads, and I just can't do that without some parmesan, but no more milk and whey shakes). I have twenty pounds of grass fed beef on its way to me as we speak courtesy of Fed Ex. I'm going to drastically cut back on or eliminate diet soda. I'll drink green tea, though, and some beer. Most of these exceptions are for willpower, not philosophical reasons - it's not that I think the green tea is important, it's just that I can't give up soda AND tea all at once and have any chance. I'm pretty sure I'll break down and eat pizza or something once a week or so, but maybe I'll cheat less.

Will it work? Stay tuned.

Osu.

One of the most surprising things about intermittent fasting, in my experience, is its ability to help people gain muscle. This runs so contrary to the "you must eat 6-8 times a day" mythology of contemporary bodybuilding that it keeps catching me by surprise.

Anyway, over the past seven months or so I thought my weight was reasonably stable because i was using the old "abs in the mirorr test." I don't have ripped abs by any stretch, but they weren't getting worse, so I figured my weight was okay. Big mistake. I actually weighed myself just before Christmas (it's a holiday celebrated by Christians around the end of the year commemorating the birth of their messiah) and lo and behold I had gained 10 or 15 pounds since the beginning of summer. Oops.

The good news is that I must have put on some muscle in that time, based on how my clothes fit. The bad news is that I didn't gain only muscle, and that's just bad. Fat slows you down, and I'm already terminally slow.

I know how to lose weight - stay on my diet. When I'm fairly strict with it the pounds do come off. The problem is I tend to cheat too much. What to do?

For whatever reason I decided to try to change my diet (once again). I'm getting older, and I tend to be tired a lot of the time, and I don't sleep very well. Why not? How should I know? It's certainly nothing my doctor can figure out. So maybe if I clean up my diet some more I'll feel more energetic.

Solution: I'm going Paleo. I've been intrigued for a while, and I've decided to take the plunge. I had my last wheat, hopefully for a good long while, this morning, oh, except for playoff football pizze (American football, Italian pizza).

This does not mean I'm reneging on IF. I'll just do IF with paleo foods - that is, eat for a 4-5 hour window only each day, but eat only foods that are allowed on a Paleo diet.

What's Paleo, you ask?

Next post, I promise.

Osu.

Here, in a nutshell, is why I'm so suspicious of self defense instructors, especially ones who come from a martial arts background.

Most of them have very little experience in actual self defense situations. Take me, for example (although I would never claim to be a self defense instructor to begin with). I haven't been in a real fight since grade school. I've never even been close to a real fight. Most martial arts teachers I know have either never or very rarely been in a real fight. What makes you think the tae kwon do instructor down the street has ever actually been in a real fight against a real thug who was really trying to hurt him?

Does that mean I know nothing about defending myself? Well, I can't know for sure, now can I? How would I find out? I'd have to put myself into situations where I was likely to get into serious fights on several different occasions and see how badly I get hurt. Guess what? I'm not going to do that. No chance.

What about bouncers? Well, as some bouncers will admit, most of a bouncer's job is dealing with drunk people who aren't too interested in fighting the bouncer to begin with. Do bouncers get into real fights? I'm sure some do, but again, I'm not sure how applicable their experiences are to more common self defense situations.

Cops? Well, I'm somewhat suspicious about generalizing a cop's fighting experience to a non-officer. What I mean is, I think that the situations most cops get into have very different dynamics than what a non-police officer is likely to encounter. That uniform seems to add a dimension to fights that isn't the same as the fights I'd get into. Police are usually armed, for one thing (I'm not, and you're probably not). I'd still take a cop's word for the reality of violent encounters over, say, my own, because I'm sure most police have a lot more real experience with real violence than I ever will.

One group that I would think does deal with a lot of violence is prison guards. Think about it - a bunch of violent people locked up all the time. The guards are in uniform, yes, but the prisoners see them every day, so they might not have the same reaction that, say, I would have if a police officer pulled me over (familiarity breeds contempt and all that). These are guys (and gals) who have to put their hands on crazy and violent people with some regularity.

Check out Chiron's blog. I got into it via Steve Perry's website (the author, not the singer. Great books, by the way). It's about violence, guns, self defense, martial arts, and a whole lot of other stuff, written by a prison guard. Good writer, lots of interesting points, and an experience I trust a lot more than that of most of the other guys out there who claim to know self defense.

There are a lot of different strength training programs out there. Some focus on timing (when to work out as opposed to which exercises to do), some on tempo, some on poundages, and so forth. One popular type of program is to describe in detail a small set of exercises - somewhere around 2 or 3, but sometimes more, - and claim that doing these particular exercises produces an overall strength increase sufficient for most people's functional needs. Some of these programs have you build up to these exercises by starting with easier versions (so the "royal" exercise might be pullups, but if you can't do them, you do assisted pullups or body rows or whatever until you can do "real" pullups).  Some of them also overdo the promotional advertising and claim truly magical results from doing that particular combination of movements.

The first such program I heard of (although it may not be the first one) was Matt Furey's Combat Conditioning. If you're not familiar with it, he basically tells you to do Hindu Squats, Hindu Pushups, and neck bridges in large numbers (as in building up to hundreds of repetitions). Many of Pavel Tsatsouline's programs/ books take this format as well. Enter the Kettlebell? Swings and... I can't remember - is it swings and presses or swings and snatches? (sorry!). Naked Warrior? Pistols and one-armed pushups. Power to the People? Deadlift and bent press. You get the idea. Simplefit is pushups, pullups, and air squats done in a variety of routines (for time, max reps, sets, etc.) In a way, many powerlifting and O-weightlifting programs take this format, at least the ones that really emphasize the 3 core lifts, but that's more a function of the competition - if you're going to snatch in competition, you'd better make the snatch a BIG part of your regular workouts.

I like these programs a lot (although some are definitely better than others). Why?

• They're simple. There are only so many variations you can do on 2 or 3 exercises, and it's certainly many fewer than can be done with 12 or 15.
• They give you a chance to really master those movements. Look at Pavel's stuff in particular. You focus on those 2 movements, but he gets really technical about how you generate tension and so forth, so you get a chance to really master the form in a way you wouldn't if you were trying to learn many movements at once.
• They require either little or minimal equipment. By definition, you aren't going to need to buy 7 different pieces of equipment to do 2 exercises.
• They are usually brief. I imagine there are some very high volume limited exercise programs out there, but most of these programs can be accomplished fairly quickly. Compare them to a typical 75 to 90 minute bodybuilding routine with 12 exercises and you'll see what I mean.
• These programs won't overkill any particular movement pattern. It's not like you're going to overtrain your quads by hitting them 6 different ways - if you're only doing 2 exercises it's fairly easy to pick 2 that won't overlap much.
• The exercises chosen are usually efficient, compound movements that involve the core nicely.
• Once you learn these movements you can focus your skill training on mastering your martial art instead of on strength training.

Are there any downsides? I think so.

• Some people might find these boring.
• No set of 2 or 3 exercises is going to adequately build strength in every range beneficial to a martial artist. In fact, one of the planes of movement that I think is most important to a fighter is usually underworked - hip adduction and abduction. Hip abductors and adductors are both very important for lateral movement and for kicking high. You're not going to find 2 exercises that will produce the right amount of strength everywhere you might want it although some might come close.

I've been trying to come up with my own royal flush of exercises, narrowing down my routines to the smallest possible handful of exercises that cover all your strength bases. I'm not sure how successful I've been, but here's my stab at things:

I figured I'd start with the core exercise for developing punching power - the kettlebell swing. Then I needed something for hip abduction/ adduction. Isometric stretching is okay, but it won't do anything but adduction, and I wanted something more general. Then I needed an upper body exercise that would work the core nicely so you'd be able to transfer all that hip drive into your punches and blocks.

Joe Berne's patented (not really) Royal Flush of exercises:

1. Kettlebell swings - works glutes, hamstrings, lower back, and shoulders - produces the "hip snap" that drives all your strikes.
2. Side lunges - works adductors, abductors, and knee extension for high, powerful kicks.
3. Scott Sonnon's 1/4 Turkish Getup. Perfect for generating punching power with the upper body. My new favorite exercise.

Ta daa... And you can do the whole routine with a single kettlebell. You might want a few kettlebells, of different weights, but you won't need two at once.

Are these enough to develop overall strength? I don't really think so. Are they enough to get a pretty good start on striking powerfully with the hands and feet AND moving yourself out of the way of your opponent's strikes? I think so.

I'm a little concerned about hip abduction (not having your hips kidnapped, I mean lifting your legs to the side) but I have a hard time finding good abduction-centric exercises. If you know of any (other than leg weighted leg raises) please post to comments.

I'm also concerned about strength imbalances. Is there enough upper body pulling with the back hand drive on the getup and the swings? I don't really think so. I'd like to add renegade rows or bodyweight rows or pullups, but that brings us to 4 exercises. Still, this is a pretty good start.

One other option is to do these routines (Pavel's, Furey's, mine, simplefit, whatever) in a rotating way. Assuming you've learned the movements, you could pick 2 days a week for strength training and alternate these routines. Week 1 do Enter the Kettlebell, then Power to the People. Week 2 do the Royal Court, then the Royal Flush. That way, any set of muscles that are left out by any one plan will most likely get hit by another sooner or later. You'll probably make slower overall progress but might be better rounded and less bored.

I'd also like to learn more about the side lunge. I tend to get knee pain from doing them, and I don't like lifting my foot off the floor with weight in my hand. I'm considering switching to reverse side lunges (you keep the weighted, bending leg in place and slide out the straightened, non-weight bearing leg) or some other variation but haven't worked out all the details yet.

Please post any nice ideas you have for very brief strength training routines!

Osu.

When I started this blog my primary concern was increasing my high intensity endurance. This term, which I just made up as far as I know, means my ability to do high intensity work (like sparring, full speed kata, etc.) for a long (relatively speaking) time. I'm sure there are other better names for this, but you get the idea. I was also interested in increasing strength, power, and skill, but mostly in building an endurance base.

One of the tools I used to do that was Tabata intervals. In case you don't remember what they are, the Tabata protocols involve 20s of high intensity work followed by 10 s of rest, repeated some small number of times (maybe 8 or 9, although I tend to do a few big sets of 8 or 9 intervals each). They're named after a Japanese researcher who was studying cyclists.

I still think Tabatas are a great way to build up strength - endurance, or whatever you call it, certainly much better than long slow distance. I personally like them more than other protocols - 30s on/ 30s off, etc., although I'm not going to argue which type of high intensitiy interval training is better, as I'm really not sure.

I was, at the time I started this blog, using kihon (basic techniques) for my exercise. That is, I'd do 20s of roundhouse kicks, rest 10 s, etc. I was basically mixing skill training with my endurance training.

Lately I've been rethinking that approach.

Why? Well, as I learn more about skill acquisition I keep noticing that practicing a skill (like throwing a kick) when you're fatigued might not only be less productive in terms of furthering your neurological mastery of that skill, it might be counterproductive. That is, compare someone who throws 100 kicks with someone who throws 1000 kicks (assuming the 1000 kick guy would be pretty wiped out by doing all those kicks). The 100 kick guy might actually end up a better kicker, because the 1000 kick guy would have practiced a few kicks, say the first 100, while fresh, but he would have practiced many of them while tired, slow, and probably sloppy. The last 100 kicks in the longer workout are actually "teaching" the kicker to kick slowly and un-explosively. The guy who does the shorter workout doesn't practice anything but kicking while fresh.

The problem is that doing my old workout, which was basically kicking and punching oneself into exhaustion, might be bad for one's technique.

The alternative?

There are two. The first is to practice your kihon separately. Do your techniques just a few times, at full power, stop before getting tired, and repeat frequently (as in even many times a day, time permitting). To build up your stamina do something completely unrelated to karate. Sprint, use a Concept II, one armed snatches, whatever, but nothing where fatigued movements will interfere with skill acquisition.

The second, and I think better option, is to mix the two approaches. I like doing kihon to near-exhaustion for a few reasons. It builds up muscular endurance specific to the techniques. For example, nothing will prepare your upper back for high volume punching better than high volume punching. It's also more efficient - you're killing two birds with one stone.

So how to mix the two without causing skill regression? I was thinking of two methods of preventing problems. The first is to alternate upper and lower body movements (so you do 20s upper body, rest 10s, 20 s kicks, rest 10s, OR 8 sets upper body, 8 sets lower body) so the local muscle fatigue never gets high enough to interfere with skill acquisition. That is, don't do kicks until your legs are rubbery - stop and punch for a while. You might be able to get a great cardio workout (your lungs and heart will be fried) without getting enough local muscular fatigue to be a problem.

Another option is to structure your workout so you "finish off" your cardio system with a more general movement, like sprints, but start off with kihon. Say you're doing (like me) 32 overall intervals (8 sets, rest, 8 sets, rest, 8 sets, rest, 8 sets). Your legs and arms might stay fresh for the first 16 total sets, but you find that you're rubbery and slow by the end no matter what. So do your 16 sets of kihon, then move into snatches or sprints or the rower or bodyweight squats or whatever for the lat 16 (or some combination of several different movements).

What you shouldn't do is punch and kick yourself into exhaustion as a regular training method. I think. I'm not positive - I don't know everything there is to know about this whole skill thing, but guys like Pavel and other trainers seem to be pointing me in this direction.

By the way, punching and kicking yourself into exhaustion on occasion is probably good for you. Just not several times a week.

Let me know what you think.

Osu.

I was listening to the radio the other day and heard a doctor being interviewed about yet another study "showing" that the slightly pudgy (1 to 30 pounds overweight) have a lower risk of dying from various diseases than do people who are not overweight at all. I didn't write down the author or anything, but it's not the first study of its type that I've heard of.

Does this mean that those of you who can see your abs should stop off at Krispy Kreme on your way home from the gym if you want to stay alive? I'm sure some people might think so, and I'm even more sure that plenty of people who have a small but growing potbelly will use studies like that one to justify continuing their lazy and self destructive lifestyle. Why go to the gym and get really lean when it just makes us more likely to die?

The truth is that there are a lot of problems with studies like this one. Let's look at a few.

Basically the way you do one of these is to study epidemiological data. You look at records of lots of people, figure out their weight category (overweight, obese, whatever) by either calculating BMI or comparing their weight to a height/weight chart, then do some sophisticated tallying of who dies of what. You find that obese people are more likely to die of heart disease, which is no surprise, and of cancer, which might be a surprise to some of us. Sometimes you find things that surprise you - like slightly overweight people die less often than non-overweight people.

Why do the studies show this? There are a few reasons.

Imagine twins, let's call them Adolf and Ben (A & B, okay?), who are both slightly overweight, say 15 pounds heavier than they should be, and it's fat. Let's suppose both are equally active, both have comparable diets, and so forth. Now let's suppose that for whatever reason Adolf gets inoperable testicular cancer - maybe he got X-rayed one too many times, maybe he lives over an old toxic waste dump, maybe he's just unlucky.

What's going to happen to Adolf? Well, he's going to die. On his way to dying he'll probably lose weight. Why? Because he has cancer. By the time he dies he might be normal weight or even underweight. Then, next year, when scientists do their studies, they count Ben as an overweight guy who lived and Adolf as a non-overweight guy who died, and it looks a little bit like being overweight is protective, when that just isn't the case.

Another problem is linked to but different from the Adolf-Ben issue. The studies can analyze who is over- or underweight, but not how they are overweight. They use height and weight to categorize people. The studies can't differentiate between a healthy, fit lean person and someone who is low in weight because they have lost the will to live or can't feed themselves. It also can't distinguish the sedentary, low weight people who are what Art De Vany calls "skinny-fat." That is, people of normal weight because of low muscle mass but still holding significant amount of fat, possibly in their organs where it isn't easily seen. These studies also can't distinguish the overweight but lean and very muscular from the overweight but just fat.

Why do these studies go on, as flawed as they are? Because every time you visit your doctor they take your height and weight. They don't measure your bodyfat or fitness levels - that would be a lot more expensive and require a lot more time. BMI or your weight relative to a height weight chart do correlate somewhat with actually being overfat or obese, just imperfectly. These studies do show how unhealthy it is to be obese, but may not be doing a good job of representing the health benefits or costs of being lean.

Lastly, another set of problems arise from epidemiological studies in general. The point of this study is to inform people's decisions to lose or gain weight, I suppose. That is, if it showed that being obese was unhealthy, presumably that might motivate obese people to lose weight. But it might be that obesity is caused by some genetic factor that also happens to cause heart disease or cancer or whatever. In other words, the fact that the obese are more likely to die of anything is not by itself proof that the obesity caused the extra deaths or that an obese person who lost weight would be less likely to die. To prove that, we'd have to take a bunch of obese people and have some lose weight and some not lose weight and see what happens.

Now it may be true that having some extra bodyfat is actually healthy, except that a lot of other more careful studies show just the opposite. How would we test this for sure? We'd have to take a bunch of lean people and force half of them to put on 15 pounds of excess fat. Or find a bunch of 15 lbs. overweight people and force half of them to lean out. This is expensive and difficult to do - we'd have to consider only subjects who could maintain their new weights for years on end, and how many people do you know who manage this?

The morale of this story is to be as lean as you can be. If you can't see your abs clearly then you're too fat (unless you can't see them because of body hair, like me, in which case you should shave your belly and repeat the test).

Plus, reducing your weight will improve your karate performance, so you're in for a win-win situation.

Osu.