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.

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.

Hi. My name is Joe and I'm a food addict.

Now you say, "Hi, Joe." Preferably in unison with a bunch of other people. Try to sound bored. Sip your coffee.

Food addict is a pretty poor term for what I have. In a trivial sense all humans are food addicts. Whenever we try to do without food we suffer withdrawal symptoms - it's called starvation. When someone claims to be a food addict in the non-trivial sense they really mean that they have strong impulses to overeat, or to eat foods that are not good for them or necessary for health. A better word for this would be compulsive overeater, but food addict sounds better in a society which treats addiction as a disease - we sound like victims of an illness, not just people with poor self control.

Food addiction in this sense is a subtle and powerful affliction. I don't think that any food addict experiences impulses to overeat as strong as a heroin addict's need to use or an alcoholic's need to drink, but the impulses are still much stronger than can be understood by people who aren't food addicts. I mean, it's not just that candy or chocolate or cake taste good - I feel a real need to eat them, under certain circumstances, and find it almost impossible to stop eating once I start.

There are other difficulties specific to food addicts. It's hard to go cold turkey on food. Like I said, starvation and all. You can go cold turkey on the problem foods - I doubt anyone ever got fat on steamed fibrous vegetables and lean cuts of meat, so you could go cold turkey on the problem foods, like anything with a high glycemic index. But it's so seductive - just one bite of pizza, it won't do any harm, right?

Another problem is the kind of social pressures you get with food. I mean, my mother in law has never offered me a needleful of heroin at the end of Christmas dinner, but she has offered dessert. I am frequently in situations where perfectly normal people expose themselves to foods that I shouldn't ever eat, like pizza, cookies, candy, chocolate, and cake. I suppose this problem is shared with alcoholics, in the sense that they are probably often tempted by alcohol at weddings, parties, social functions, but I have to say that I bet I see a lot more simple carbs available than alcohol.

There are also some insidious ideas that make it a little bit harder to go cold turkey on bad foods. One is the "Cheat to Lose" diet/ idea. It's written by a guy named Joel something... (google it if you care) who sounds very smart and has a really wonderful New Jersey accent. He basically claims that while dieting your leptin levels drop, and with it your metabolic rate, which means your body will burn fewer calories. By overindulging periodically, and he means eating a bunch of cookies or ice cream or pizza, things with lots of carbs and fat, you reset your leptin to pre-dieting levels, speed up your metabolism, and actually wind up leaner in the long term.

Does this work? I'm not sure. It makes sense. Suppose eating an extra 1500 calories once a week boosts your metabolism so that, on average, you burn an extra 250 calories a day. Eat 1500 extra - (7 X 250 extra burnt a day) = 250 calorie per week deficit. Suppose those extra 1500 calories boost your metabolism by 400 calories per day. Bigger deficit. Suppose you could get the same boost by "cheating" by only 1000 calories. Assume that not all of the extra calories actually get absorbed - you might be creating an even more beneficial deficit.

On the other hand, suppose you pack in an extra 3500 calories on that cheat day. You might not be better off. Or suppose that like me, you're a food addict, and you use the cheat day concept to justify overeating for three straight days (I'm sick, all right?) Then... not so good.

There are other reasons to think a planned, periodic cheat day might be good. Some people find it easier to stick to a restrictive diet if they "promise themselves" some sweets or pizza or whatever. You know, "I'll be good, but on Sunday I'm eating a whole pizza and a pint of Ben & Jerry's!" I find that I have mixed success with this approach. Planning to overeat on Sunday tends to make me overeat on Saturday as well, then Monday and maybe Tuesday (I'm eating a whole pizza tomorrow, so half a pint of ice cream tonight won't be so bad...) It's not rational, but that's the point I'm trying to make - food addicts don't make rational food choices. That's why we're addicts.

On the other hand, it has seemed to me in the past that cheating once in a while on a limited basis has helped me lean out.

Two conclusions. First, some people will find the planned cheat day to be liberating, while for others it will lead them into big problems. You have to figure out which you are.

Second, cheating may help you lose weight faster, but that doesn't mean it's the healthiest way to eat. Given how good calorie restriction is for the health of animals I think that the dieted state - lower leptin, slowed metabolism, etc. - may not be great for short term weight loss but it might be better for your health. Just a suspicion. That insulin surge and re-setting of hormonal levels and metabolism that you get from those cheat days might not be good for you.

If you're a martial artist and a food addict prepare for a lifelong battle against the creeping advance of bodyfat. Fat slows you down. Being slow gets you hit. And if you're wondering why I'm writing this post today of all days, remember that yesterday was Halloween. I ate something like 75 chocolate bars, peanut butter cups, boxes of dots, and god only knows what else last night, and so help me I might do the same thing again tonight.

Do as I say, not as I do.

Osu.

Let's recap.

There is some disagreement about the healthiest way to eat.

Everybody (I mean everybody sane) agrees that: 

• You should eat as many fresh non-starchy vegetables (not potatoes, stuff like that) as possible in as much variety as possible (so you get the greatest variety of nutrients).
• You need some essential fats (think fish oil, grass fed beef, flaxseed oil), probably more than you're currently getting.
• You should avoid simple sugars and refined (white) flour - eliminate them from your diet completely if you can. Ditto for corn syrup.
• You should eat a variety of fresh fruits, nuts, and berries every day, although not in unlimited amounts.
• You absolutely need a variety of vitamins and minerals, which you could probably get if you followed the items above.

Almost everybody agrees that:

• You need a significant amount of protein, preferably from a variety of sources (not just chicken or just fish).
• You need to limit the total amount of carbohydrates you eat - either avoid them altogether or eat them only when combined with protein and fat.
• If you eat carbs, whole grains are better than refined, low glycemic index better than high glycemic index.
• You should eat lots of fiber.
• You should eat a multivitamin daily to avoid any possibility of vitamin or mineral deficiency.

There is disagreement about:

• Whether the preponderance of fats you eat should be saturated or unsaturated (saturated fat + refined carb = heart disease BUT without refined carbs it's not as clear).
• Whether or not to indulge in cow's milk in any form.
• Whether all nuts are okay (many avoid peanuts, etc.)
• What other supplements, if any, you should take (Vitamins C,E, minerals, etc.)
• A few other things...

Imagine some random guy who is a practicing martial artist and is quite overweight. To lose weight he avoids carbs and mixes fat in with his meals. But he's not much of a cook, so he makes chicken salad for himself. A really simple chicken salad - chicken meat and mayonnaise. That's it - no celery, no veggies, not even any spices. And that's all he eats. He eats chicken salad and drinks water.

Will this guy lose weight? Yeah, probably. The chicken salad should fill him up and keep blood sugar levels relatively stable, and he'll slip into ketosis in a couple of days and probably feel fine. As long as he eats enough of the chicken he should be able to maintain muscle mass. But we all know that this guy won't stay healthy for long. A diet like this (I made up an extreme example to make a point) is missing too many crucial nutrients. I can't begin to imagine what would happen after a few months on the chicken salad diet, but it won't be pretty.

What kind of nutrients are we talking about? Now we're getting into the areas of health and performance. From a pure weight loss perspective the chicken salad diet isn't too bad. But health, and therefore performance, will decline without a little help.

The first nutrient we have to worry about as martial artists is protein. The chicken salad diet actually has that covered. Your body needs lots of protein, especially if you do a lot of strenuous exercise. Don't believe me? Want to pull out some studies that "prove" that you don't? Just think about it. Exercise damages muscles. Hard exercise damages muscles a lot. Muscles are made of protein. What do you think you need to have around your body to repair them? Protein. I'm not saying you need professional bodybuilder amounts, but I'm not sure that wouldn't help. I will say that the more protein I eat (which has never passed 175g/day or so) the quicker I recover, the less sore I am, and the faster my muscle injuries heal.

There are a large (some would say bewildering) variety of diets out there aimed at helping us lose excess body mass. Which one is best? That's a complicated question, and one I may not be qualified to answer. But it's not so hard to examine what they have in common and what mechanisms they use so we can pick and choose the elements that fit each of us best.

Diets work in a variety of ways. We can simplify things by sorting some of the most common elements into categories.

• Psychological methods: Many diets include (or consist entirely of) ways to increase our motivation or willpower. Weight Watchers has the famous AA-style meeting (group of people announcing their weight loss together, applauding, sharing stories, etc.) Lots of diets also include other psychological tricks, like eating a small dessert every so often so you don't feel like you're depriving yourself. Nothing wrong with these, but for many of us overcoming eating compulsions are more than just a matter of motivation and willpower.
• Physical alteration: I'm talking about things like gastric bypass surgery. This will stop you from pigging out by making it physically impossible. You can add drugs into this - things like fat blockers that work because if you eat too much fat you get nasty oily diarrhea. Probably not the best choices for martial artists.
• Delivered food: Some plans deliver all your food to you so you don't have to measure anything and so you instantly know how much you ought to be eating. Not a terrible choice if you can stomach the food and afford the bills.
• Volumetrics: Diets like this one (and the concept isn't new and wasn't invented by the Volumetrics author) get you to eat foods that take up more space or weight for the calories so you don't eat as much. For example, suppose you pig out on Ben & Jerry's. You can probably polish off a pint no problem. That's 1100 - 1300 or so calories. On the other hand, suppose you eat all the lettuce you can eat - I mean really chow down - eat until you're so full you're about to bust. I bet you won't have anywhere near 1100 calories worth of lettuce inside you. By eating foods more on the lettuce end of this continuum you'll eat fewer calories without feeling hungry or deprived. This works, and in practice ends up mimicking many of the recommendations made by other diets. I use a version of this - I drink a fiber drink before every meal, to fill myself up somewhat and make myself less likely to eat a large amount of calorie containing food.

This isn't a complete list. There are other types of diets out there - the coffee and grapefruit diet (grapefruit contains some chemical that slows the metabolism of caffeine, so this is really the super caffeine diet), watermelon diet, and probably hundreds of others. But the most popular and most successful diets all depend on another mechanism. Atkins, the Zone, and South Beach are all slightly different ways of controlling insulin response.

I, and many others, believe that insulin sensitivity problems are at the root of a great deal of the compulsive eating we find in people. What am I talking about?

When you eat carbohydrates your body breaks them down into simple sugars (glucose) as they travel through your mouth and stomach. They then cross from your small intestine into your blood. So, you eat, and a little later the glucose levels in your blood start to go up. The more carbs you eat the faster this happens. The higher the glycemic index of the carbs (the easier they are to digest) the faster this happens. Eat one gummi bear - not much impact. Eat a bag of them - lots of impact. Eat a big bowl of oatmeal (low glycemic index) - slow rise in blood sugar. Eat a big bowl of Frosted Flakes - fast rise in blood sugar.

The sugar in your blood isn't very helpful. To use the sugar for energy your body has to get it into your cells - brain cells, muscle cells, skin cells, anything. The problem is that the sugar doesn't cross over so easily. Your cells need insulin to get the sugar from the blood into the cells where they can be burned and used for energy. Insulin is like the key that opens the door between the blood and your cells.

So, eat a few carbs, blood sugar goes up a little. Insulin is made. Sugar gets from blood into cells. Blood sugar goes back to normal. Insulin gets metabolized. Cells happy. You happy.

BUT... Eat lots of high glycemic index carbs. Blood sugar goes way up. Lots of insulin is made. Sugar gets into cells faster. With lots of insulin around, blood sugar goes way down.

This causes a bunch of problems. When blood sugar falls this way people your body tries to get it back to normal (our old friend homeostasis) and you crave carbs. That's why some people can eat a big bowl of carbs - like plain pasta or candy or whatever - and feel hungry again an hour later. Their blood sugar skyrocketed, then insulin skyrocketed, then blood sugar plummeted, and the low blood sugar caused cravings. Boom - overating binge.

When this is repeated over time the body's insulin receptors get damaged. Imagine you're opening a lock over and over again. Under normal usage the lock lasts a lifetime. Now slam the key into the lock as hard as you can every time you open it. The lock will get worn out or broken a lot quicker.

When the insulin receptors (the locks on the cells) get damaged they don't work as well. Sugar stays in the blood for a longer period of time. The body, worried about the high blood sugar, makes even more insulin. By the time the working receptors can clear the sugar out of the blood there is so much insulin around that they clear too much sugar out, resulting in an even worse low-blood-sugar crash. The excess insulin also further damages the receptors, further reducing insulin sensitivity, so the situation keeps getting worse. You crave more and more simple (high glycemic index) carbs to stabilize your blood sugar.

Meanwhile, what do you think is happening to all that sugar getting into your cells? It would be nice if you had a lot of energy and found yourself craving exercise, but that isn't what happens. Instead, when there's all that insulin around, your body figures that there's excess energy and does what any responsible consumer does - saves some for a rainy day. Meaning that it manufactures fat. So you crave more food, and when you eat it your body rapidly turns it into stored fat. Your energy levels are low (because of the crashing blood sugar levels) so you don't feel like exercising.

Result? Go to any mall in America. Go to the food court. Look around. Not pretty, is it?

Solution? Never let your blood sugar rise quickly. Never.

How do we avoid that? There are a few solutions. Dr. Atkins said not to eat carbs. No carbs, no spike in blood sugar levels. Your body will start making ketones for energy instead. Ketones are made directly from fat. It's really easy for your body to turn fat into ketones, so your energy levels get a lot more stable and you don't crave food you don't need. No sugar in the blood means low insulin levels so your body isn't always trying to store fat.

The Zone does things a little differently. By never eating too many carbs or carbs by themselves or any high glycemic index carbs the Zone won't put you into ketosis but it will make your blood sugar rise much more slowly. Slow blood sugar rise, no big spike in insulin, no big insulin crash, no damage to insulin receptors. South Beach does the same as the Zone with slightly different mechanics - by telling you to eat low glycemic index carbs and by mixing those carbs with fat and protein and fiber the rate of blood sugar increase is slowed, and you avoid all the negative ramifications like insulin insensitivity and obesity.

There are some other ways to keep insulin levels down. Intermittent fasting (IF) has you avoid eating altogether for period of time, either every other day or 18 hours every day. While you're fasting your blood sugar is low, so insulin levels stay low, and your receptors get a chance to recover. This is my diet of choice.

What's the conlusion? If you're young you can get away with eating things like french fries or whatever, for a while. But you're damaging your insulin receptors and you'll pay for it later. To keep energy levels stable you should:

• Eat only low glycemic index carbohydrates, if you eat carbohydrates at all.
• Only eat carbs with fat and protein - never alone (this slows the breakdown).
• Eat fiber with every meal (fiber slows the breakdown of carbohydrates in the gut).
• Never, ever eat refined flour or sugar. Or at least avoid them.

The pasta meal before a big athletic event is just a bad idea. Sorry, pasta lovers.

There's a little more I have to say about diet, but I'll save it for another day.  I do intend to break all this theory down into concrete recommendations that you can follow.  Soon.

Shalom