Part of me getting my life back on track was reversing the damage that years of a bad diet had caused.

 

Here’s the thing though, I didn’t think my diet was that bad. I ate plenty of whole grains and raw vegetables and I very rarely had any dessert.

 

Something was wrong, though. My shorts from college still fit, but they were getting tighter and tighter all the time. My belly was also starting to spill over the top.

 

This was unusual for me. I was always one of scrawny kids growing up. In middle school some guys would wear a t-shirt to the pool so no one would make fun of them for being overweight. I wore one so that no one would make fun of being able to see my rib cage.

 

I should mention that during this time I was incredibly physically active. When I started gaining weight I was doing p90x with a friend and doing pickup sports. Even after I quit p90x, I was still doing regular home workouts and on the weekends I would meet up with friends to do workouts so intense that we often had guys nearly vomiting.

 

How did this happen? How did someone whose genes were set to “scrawny” throughout all of childhood suddenly find himself steadily gaining weight despite a healthy diet and tons of exercise?

The Conventional Wisdom

 

If you ask someone, even most doctors, why some people gain weight and become obese, chances are the answer will be something similar to the following:  “People get fat because the eat too much and exercise too little.”

 

This is formally called the energy balance hypothesis.

 

You might have heard it called “calories in, calories out,” or maybe “a calorie is a calorie is a calorie…”

 

I call it the Catholic theory of obesity, both because it essentially appeals to two of the seven deadly sins (gluttony and sloth), and because it is basically a religious dogma (disclaimer: I have nothing against religion. In fact, I am a Christian myself and unashamed about it).

 

The theory is well meaning and is close enough to reality to give it some credibility. Those who believe in this theory say that it is indisputable science because it is based off of the 1st law of thermodynamics, which isn’t in dispute.

 

You remember the first law of thermodynamics, it’s the one that tells us that energy is neither created nor destroyed, so the change in energy in a system is going to equal energy in minus energy out.

 

You can write it out like this:

 

(delta)Energy = Energy(in) – Energy(out)

 

And of course when it comes to food, energy is measured in kilocalories, or Calories for short.

 

In other words the law says that the change in Calories in your body equals Calories in minus Calories out. Nothing controversial there, everyone agrees with that.

 

There are several problems however with assuming the first law of thermodynamics supports the energy balance hypothesis.

The Issue of Causality

First of all, and this is the single most important point to keep in mind in all of science, there is no causality implied in the first law.

 

The entire reason the science is so difficult in the first place is because human beings are hard-wired to constantly be on the lookout for causality. So, we see the first law and try to apply it to weight loss and we immediately see an arrow of causality going from right to left:

 

(delta)E <– E(in) – Energy (out)

 

Notice that this is a possible interpretation of the first law, but it’s not the only one. In theory, you could manipulate the right side of the equation so drastically that you alter the right side as well. This is what they do on The Biggest Loser. They force the contestants into a diet and exercise routine that just isn’t sustainable, and typically, the weight loss doesn’t last.

 

But of course, it could be the other way around. Maybe people eat more and exercise less because they are getting fatter.

 

Maybe it’s the case that neither side of the equation is the causal factor. Maybe there is some X-factor that is influencing one or both of these things. In fact, this seems to be the closest to the truth:

 

X-factor –> (dealta)E –> E(in) – E(out)

 

Some X-factor is causing us to gain weight, which ends up working itself out on how we balance our energy intake versus energy expenditure.

Independent Versus Dependent Variables

One of the most staggering assumptions made by those who think we need to eat less and exercise more is that Calories in and Calories out are independent variables.

 

What if exercising makes you hungry?

 

What if overeating makes you more active?

 

What if other variables are influencing what is happening here?

 

One thing that should be immediately obvious is that if you put someone on a calorie-restricted diet they will get hungry. Now, some of this hunger is actually psychological. Last time you got hungry at noon, it wasn’t because your body needed food it was because you’ve been conditioned to eat lunch at that time. But, some of it is biological. The other thing that will become clear is that in general those on calorie-restricted diets have less energy. You are affecting how much energy they expend by changing how much they consume.

What Do You Mean “Calories Out?”

Calories in is pretty simple, the only way that energy enters our system is through our diet. How much you eat = Calories in.

 

You could say that technically “Calories in” is slightly less than what we eat because we don’t digest all of it, but it’s probably easier to just lump those undigested bits in with “Calories out” and say that the Calories that you eat are your Calories in.

 

Calories out is a bit more complicated, however. I’ve just mentioned that there’s some parts of your food that don’t get digested. There’s also some calories that get burned digesting the food that your body does absorb. There’s also obviously the calories burned during exercise. Then, there are the calories burned doing everyday activities like walking to your car or picking up your kid. Then, there’s your Basal metabolism, the calories being burned in the background. They are being burned while you are sleeping.

 

It’s the metabolism that makes Calories out so tricky. In all the typical diets and weight loss advice, you are invited to think of your metabolism as a constant, but this is frankly ridiculous. Not only do you not have the slightest clue how many Calories your metabolism is burning, you have no idea how often it switches gears. If you get in the pool for instance, your metabolism will start working harder. This is because one of the primary things that your metabolism is doing is keeping your body at 98.6 degrees Fahrenheit. The water sucks the heat out of you in a way that the air doesn’t  (think about what happens when you run a hot frying pan under water), this causes your metabolism to burn more calories to keep your body temperature up (remember, heat=energy).

 

Most of the energy you will burn in your life is burned by your metabolism. Focusing on the exercise portion of Calories out while ignoring the metabolism is like ignoring offense and defense at football practice so you can work on extra points.

What About Biology?

Perhaps, the most inexplicable issue with the Energy Balance Hypothesis is that it takes the biological question of obesity and entirely skips biology.

 

It starts with physics, as we’ve seen, and then jumps straight into psychology- how can we get people to eat less and exercise more.

 

Now, I’m a huge believer that psychology is going to play a critical part in someone having success losing weight, but when we are talking about things like weight gain and weight loss, don’t you think biology should enter the discussion at some point?

 

If calories in and calories out are the only things we need to worry about, we might just as well all start eating gun powder. Gun powder is less calorically dense than protein, fat, or carbohydrates. Sure, gunpowder doesn’t really have any nutrients and I think it might be toxic, but those sound like questions of biology. We’ve already fixed this problem with physics.

 

Now, I don’t want to be using a straw man here, people who advocate the Energy Balance Hypothesis will talk about biology, but when it comes to weight gain and weight loss they will always do so only to bring it back to Calories in versus Calories out.

First Principles

The very first thing you should do in science, before you even come up with a hypothesis, is to define the problem in a way that contains as few assumptions as possible.

 

When it comes to obesity and weight gain, the usual definition of the problem is that people eat too much and exercise too little. As we’ve already seen, this definition of the problem is really a hypothesis, and one that is full of  assumptions, most of them unlikely to be true.

 

So what would be a better way to define the problem? Here’s how I would define it: people who are getting fatter are storing too much fat on their bodies.

 

It sounds silly because it’s so obvious, but now instead of your next thought being “how do we get people to eat less and exercise more,” your next though is likely to be “huh, I wonder what regulates fat storage?”

 

As we’ll see later on, that is exactly the right question.

What Regulates Growth in the Body?

Before we look at a specific example of growth in the body (weight gain), it might be helpful to think about how growth works in the body in general.

 

Imagine for a second that I showed you a picture of my son at one year old, and then another one of him at two. I tell you that I was very concerned with his pace of gaining weight. in just one year, he doubled his weight! What are we going to do?

 

Obviously you would think I was being foolish, my son wasn’t getting fatter, he was growing taller.

 

His genetic blueprint is set for him to be growing at his age, so his body is releasing a hormone called growth hormone and this is causing him to grow, which means he ends up in a state of positive energy balance, taking in more calories than he burns.

 

In other words, here’s what is happening when a toddler doubles their weight:

 

Genetic blueprint –> growth hormone –> (delta)E –> E(in) – E(out).

 

You’ll notice that parents instinctively know this. If a child starts eating twice as much as normal, it’s because they are in a growth spurt. I’ve never met a parent that thought that their child was consciously deciding when it was time to grow and adjusting their caloric intake accordingly. Every single one of them (correctly) recognizes that growth is the cause, eating is the effect.

 

Maybe a more interesting example might be to consider what happens to children as they go through puberty. Again, they will be growing which means they will have a positive energy balance during this time, consuming more calories than they burn. But this positive energy balance will go in two extremely different ways for boys and girls.

 

Coming into puberty, boys and girls have bodies that are remarkably similar. Their sexual organs are different and girls have about 6% more body fat than boys, but for the most part if you dressed a girl up in blue you could convince most people that she is a boy. That all changes in puberty.

 

When boys hit puberty, they get stronger and leaner. Body fat goes down and muscle mass goes up.

 

The girls, who again entered puberty with just 6% more body fat than boys, will gain body fat and finish puberty with about 50% more body fat than their male counterparts. Even more remarkable, this fat isn’t uniformly spread across their bodies, it gets disproportionately located in their breasts, butt, hips, and thighs. For most adolescent girls, very little fat accumulates around their stomach, the place where fat almost always goes with boys and men.

 

So what on earth is going on here?

 

Again, this is genetic, and hormonal. This time growth hormone is present like before, but sex hormones like testosterone and estrogen are now also quite active. These hormones drive the divergence between male and female bodies during puberty.

 

This example is even better than the first because not only do we have weight gain, but this time there are also implications for body fat. Just like before, the reason for the growth is hormonal. The energy balance just falls in line with the changes the hormones are making.

The Fat Regulation Hormone

 

So this leads us to the question, what is the primary hormone that regulates fat storage?

 

The answer, in a landslide, is insulin.

 

We’re going to get a little technical here but stay with me, I promise I’ll try to explain it in a way that makes sense.

 

The fat in your body exists in two different forms (that we are interested in): fatty acids and triglycerides. The fatty acids are the form that gets used for fuel. If at any point you are “burning fat,” it means you are using fatty acids to fuel your energy expenditure. Triglycerides are the storage form of fat. A triglyceride is three fatty acids bonded together with a glycerol molecule.

 

In it’s triglyceride form, it can’t exit the fat cell to be burned. Think of it like this, I have a three piece sectional couch in my living room from Ikea. You can think of it as a triglyceride and my living room as a fat cell. There’s no way that you can get this thing out of my living room without first breaking it down into its three separate parts.

 

Anything that works to combine fatty acids into triglycerides for storage is going to make you fatter, and anything that breaks it back down into fatty acids so they can be burned is going to make you leaner.

 

So how does insulin relate to what I just mentioned?

 

Insulin regulates your fat metabolism through two enzymes: Lipoprotein Lipase (LPL) and Hormone-Sensitive Lipase (HSL).

 

LPL is like a mover whose only job is to put together the Ikea sectionals and store them in my living room. It turns fatty acids into triglycerides and stores them as fat.

 

Insulin up-regulates the activity of LPL on your fat metabolism, meaning it tells LPL to get to work storing body fat.

 

If LPL is the worker assembling the Ikea sectionals and putting them in my living room, HSL are the workers breaking them down and taking them back out.

 

In the medical jargon this is called “fatty acid mobilization,” meaning that the fatty acids that were formerly trapped in storage in the form of triglycerides have now been mobilized to be used as energy.

 

Insulin suppresses HSL activity. This means that when insulin is calling the shots, the workers who are breaking down those Ikea sectionals get laid off. And as we’ve seen, insulin also increases LPL, meaning those workers get replaced with ones who fill my living room with sectionals. And my living room starts to fill up really quickly.

 

Oh, by the way, did I mention that the other thing that insulin does is create new living rooms (fat cells) to store even more Ikea sectionals in?

 

Insulin is the only major hormone that unambiguously works to make you heavier. Most hormones actually go the other way, which makes sense when you think about it. Adrenaline would be pretty useless if it didn’t release some stored energy that you could use for either fight or flight. What good would testosterone be if it just told men to reproduce without giving them a boost of energy to do what they need to do?

 

The other major hormone besides insulin that has the potential to make you lose weight is the stress hormone cortisol. Cortisol increases both LPL, which has the potential to make you fat, and HSL, which has the potential to make you lean. This is why some people lose weight when they are stressed while others gain weight; it all depends on the net effect that cortisol has, which could go either way.

 

So we have our culprit, but the question is, what drives insulin?

The Fattening Foods

 

Under the energy balance hypothesis, a calorie is a calorie. No food is inherently any more fattening than any others. Some foods should be avoided because they contain calories but have little nutritional value (you’ll hear the phrase “empty calories” a lot), but each food is only fattening to the extent that the extra calories put you into a positive energy balance.

 

Once you understand that insulin is what is driving fat accumulation, the question becomes what are the foods that stimulate the release of insulin?

 

The most generic answer is carbohydrates, especially sugar, high GI (glycemic index) carbs, and refined carbs.

 

So in other words, things like bread, pastries, fruit juice, pasta, crackers, soda, beer, cereal, rice, potatoes, and corn.

 

One thing that is worth noticing is that a lot of the foods that I just mentioned actually formed the base of the now (thankfully) defunct food pyramid.

 

Another important thing to notice is that all the foods mentioned are incredibly cheap. In general, the more poor someone is the more likely they are to be fat and this is a big reason why.

 

Here’s what you need to know about carbs. They break down into glucose, or what we would call blood sugar. Some of this glucose can be stored in the liver and some can be stored in our muscles, but not much. We have to do something with the rest because we can’t have too much in our blood.

 

So when our blood glucose levels get too high (from eating lots of carbs), we release insulin to clean things up and store the excess glucose as fat in our body.

 

The biggest offender is sugar. Sugar (sucrose, but I’ll include high-fructose corn syrup and other forms of dietary sugar in here) is half glucose and half fructose (high-fructose corn syrup is most commonly 55% fructose). Fructose is the part that is sweet. Fructose can only be metabolized in the liver, which has the necessary enzymes. This fructose gets converted into fat more readily than anything else and can lead to non-alcoholic fatty liver disease. In addition when you consume sugar, the glucose portion raises your blood sugar causing a release of insulin that will also clean up all the fructose that was converted to fat by the liver.

 

Perhaps the worst part about sugar is that it leads to insulin resistance, meaning your body has to secret more insulin in response to a given level of glucose. This is bad, because not only does insulin make us accumulate fat, it also makes it so that we can’t burn the fat.

 

Not only does consuming sugar raise your insulin in the short term, it increases the amount of insulin that you will release in response to future carbohydrate consumption.

 

If you want to lose weight, sugar is your biggest enemy.

The Great Medical Disconnect

What I’ve just argues is this:

 

Carbohydrates –> Insulin –> Fat.

 

The amazing thing is that if we break it down into two statements, neither one is remotely controversial:

1. Carbohydrates –> Insulin
2. Insulin –> Fat

 

These are both taught in any medical school and can be found in most biochemistry and endocrinology text books.

 

Where people lose their cool is if you put the two together and suggest that it has anything to do with the obesity epidemic.

 

Saying “Carbs drive insulin” and “insulin drives fat” are both okay, as long as you don’t say “carbohydrates drive insulin, insulin drives fat” (or even worse, the logically equivalent “carbohydrates drive fat”).

 

When it comes to obesity, the conventional wisdom dictates that you have to say that overeating and under-exercising cause people to get fatter.

 

The great medical disconnect is the fact that everyone knows what drives fat accumulation, but no one will admit that its the same thing that makes us fat.

 

You can even have examples of a single textbook saying that high glucose levels triggering the release of insulin is what is driving fat accumulation, but then later say that the cause of obesity is eating too many calories while expending too few.

 

In other words, I’m not suggesting anything new, I’m simply arguing that the same thing that makes us fatter is probably what makes us fat.

 

Let me say that again, all I’m arguing is the same thing that makes us fatter is probably what makes us fat.

 

Everyone agrees on what makes us fatter, I have no idea why we can’t agree about what makes us fat.

Reversing Course

 

That brings us to the section that people likely care the most about: what can you do to fix your metabolism, lose weight, and cut your chances of acquiring a chronic disease like type 2 diabetes?

 

The best answer, as far as I can tell, and the one that will work for the most people is to restrict carbohydrate consumption, especially sugar.

 

My preferred diet, which I will be writing about soon, is the slow-carb diet, but the good news is that most diets work, even if they have the wrong mechanism for helping you lose weight.

 

According to a CDC survey from 2000, Americans eat over 50% of their calories in the form of carbohydrates. This means that any diet that cuts calories is going to result in a drastic decrease in carbohydrate consumption, even if it’s a “high carb” diet.

 

The truth is there are virtually no high carb diets in existence besides the standard American diet that people default into. When a diet is classified as “high carb” it means that carbs make up a larger percentage of the diet than do fats and protein. Since these high carb diets usually come with calorie restrictions, you end up eating far fewer carbs.

 

This can be contrasted with high fat diets which are effective for weight loss and are almost always ad libitum, meaning you can eat as much as you want (literally “according to your pleasure”).

 

Additionally, pretty much every diet on the market is going to cut the worst offenders out of your diet: sodas and sweets, processed snacks and things of that nature. Most diets do this because they consider these foods “empty calories” and so if you are keeping calories under control, they have to go.

 

I disagree with the “empty calories” notion and would contend that those foods play an active role in wrecking your metabolism and making you fat, but since diets that follow conventional wisdom do the right thing and get rid of them, I won’t press the point too much.

What About Fruit?

 

Probably the most controversial implication of this argument is that as far as I can tell, it’s a good idea for a person who is trying to lose weight to restrict their fruit consumption (at least for sweet fruits: grapes, bananas, pineapples, mangoes, oranges, etc. Most of the fruits that aren’t normally considered fruit are fine: tomatoes, avocados, cucumbers, etc.).

 

This is one of the areas that the Conventional Wisdom really likes to attack low-carb diets. Why would we ask people to stay away from fruit? Fruit has so many vitamins and minerals that are an essential part of a healthy diet.

 

I completely agree that there are a lot of benefits to fruit and in a perfect world I would recommend them, but we don’t have perfect conditions. Right now, we are specifically talking about the very imperfect condition of having accumulated excess body fat. Fruit may be healthy in a normal diet, but I don’t think it is helpful to include in a weight loss diet.

 

I will say that fruit, despite the presence of the harmful fructose, is not nearly as bad for you as most sugary foods and beverages. First of all, you would need to eat four or five apples to get the amount of fructose of one glass of apple juice. Who eats five apples in a sitting? Most people don’t even eat that many in a day, but someone could easily put two glasses of apple juice away at breakfast.

 

The second thing to note is that fruit contains quite a bit of fiber, which gets stripped out in the juicing process. Fiber is basically anything that isn’t digestible, and it’s presence in fruit prevents the full absorption of the fructose. In other words when you eat an apple, not only does it have a fraction of the fructose as a glass of juice, but because of the fiber you won’t absorb it all.

 

This means that the person that drinks two glasses of apple juice at breakfast would have likely needed to consume more than 20 apples to ingest the same amount of fructose. When was the last time you ate 20 apples in a day?

 

So all that seems to indicate that if you are thin, fruit doesn’t need to be very high on your list of concerns. However, if you have a lot of weight to lose, the name of the game for you is insulin management and the best way to go about that is to restrict your carbohydrate intake, and that includes fruit.

 

Save fruit for cheat day.

 

Vegetables are fine.

Final Thoughts

 

I think knowing what makes us fat is an incredibly important first step, but it’s just a first step. A diet that really works doesn’t just need to provide an effective game plan for weight loss, it also needs to be one that you can follow.

 

Adherence to diets can often be brutally difficult and most people who lose weight end up gaining it all back and sometimes more.

 

In the future I’ll go over some of the keys to creating a healthy and flexible diet that doesn’t feel restrictive that you can adhere to in the long term. For now, it’s important to keep in mind that it is refined and easily digestible carbs, especially sugar, that are wrecking our metabolisms and causing us to gain weight.

 

Here are some resources to tide you over until my future posts:

 

Eating Academy is the blog of Dr. Peter Attia and is a fantastic resource. It gets a little technical, but if you stay focused you’ll be rewarded with deeper insights into the science of nutrition than most people have.

 

Here’s a great post he had where he was arguing one of the points that I made above, namely that most diets are actually low-carb diets: http://eatingacademy.com/nutrition/why-weight-watchers-is-actually-a-low-carb-diet

 

Speaking of Peter, here’s a great lecture for those of you who prefer to watch a video. In it he shares how he lost weight and became healthier thanks to a form of ketogenic diet (as a side note, keto is on the far end of the carb restricted spectrum. While I think it can be an effective diet, it’s not usually the one I recommend just because it seems like adherence would be so difficult): https://www.youtube.com/watch?v=NqwvcrA7oe8&t=3770s

 

My favorite book on this topic so far is Why We Get Fat and What to Do About It by Gary Taubes, which was my main source for this post. It’s currently on my exclusive list of most recommended books. You can read my review of the book here: http://thematthewkent.com/books/why-we-get-fat/

 

Speaking of Gary, here’s a fantastic lecture he gave that I highly recommend: https://www.youtube.com/watch?v=lDneyrETR2o&feature=youtu.be