The Skinny on Weight-Loss: How it Works and How to Do It

The common wisdom regarding how to lose weight is simple: eat less. If you consume less calories, which are a measurement of units of energy, than you expend, you’ll lose weight.

This thinking is based in a principle of physics, called the first law of thermodynamics. That’s the one that states energy cannot be created or destroyed, only transformed from one form to another.

Sounds pretty solid. So it makes sense to go for the snack cookie, because it’s only 100 calories! Says so right on the bag! I can take a walk later and “burn this off.”

The problem with the calories in, calories out argument is not that it’s wrong, but that it’s woefully incomplete.

Besides micronutrients, which is the category that includes all of the essential vitamins and minerals one needs to be healthy, there are three macronutrients: carbohydrate, fat, and protein.

People focus on micronutrients a lot in the public culture. Many of which are half-truths exaggerated by PR campaigns. For example, the claim that bananas have a lot of potassium (they have some, but other common foods like potatoes and spinach have more). Or that milk has a lot of calcium (ditto, greens like kale have more). Or that oranges have a lot of vitamin C (red bell peppers crush oranges with three times more vitamin C).

Besides genetics, macronutrient intake is what really makes your body composition what it is. Exercise matters much less than what you eat. If you go run and then eat badly, or think you can “burn off” something by exercising, you may very well be fooling yourself.

The three macronutrients of carbs, fats, and protein are the three sources of calories. And not all calories are created equal. Ingesting 100 calories of carbs versus 100 calories of fat versus 100 calories of protein have different effects in the body. This would seem obvious, but proponents of the calories in, calories out philosophy ignore these differences.

Carbohydrates are the products of carbon and hydrogen that plants combine, from the carbon dioxide in the air and the water they receive. So carbs are in plants. That’s why there are no carbs in ribeye, for example. But they are in wheat and other grains, which are used to make most processed foods today, like breads, cookies, cakes, chips, pasta, and so forth.

Now, carbohydrates get broken down directly into glucose in the body. Glucose is essentially sugar. So eating a piece of bread is not much different than eating Skittles. It becomes the same thing. Sucrose is table sugar, and fructose is in fruit and also in high-fructose corn syrup, which is an easy and cheap sugar to manufacture and put in everything. But they all get broken down more or less right away into glucose. Basically carbohydrate, sugar, and glucose are synonymous. Sometimes people talk about blood sugars or blood glucose. It’s the same thing.

The body has two fuel sources: glucose and fat. The fat on your body is stored energy. Protein, on the other hand, is used to build practically everything in your body, but it’s not really a good fuel source in and of itself. If you ate nothing but protein you would crash and burn very fast. But you can eat fat or carbs and keep going for a long time.

When you ingest carbs or sugar, your blood glucose levels spike. After a couple hours or so, they peak, and then they drop, sometimes lower than they were before. This is why eating a candy bar or even a baked potato (carbs too) will give you instant energy, but a little while later you’ll be crashing and looking for another one real quick. Then you’ll just be on a blood sugar roller-coaster throughout the day, with fluctuating energy levels.

Another important thing that happens when your blood glucose levels go high, is that your pancreas secretes insulin. Insulin is a hormone that is sent to clear out a lot of the extra glucose and get it out of the blood stream. Too much glucose is dangerous, and insulin sweeps some out to keep levels normal. This is what goes wrong in diabetes, which is a disease of blood glucose being too high for different reasons.

Insulin has two places to send the glucose: your liver and your muscles. You can store glucose there in a form called glycogen. Glycogen in just glucose sitting in the muscle and liver to be used when needed. Think of glycogen as glucose that waits on the sidelines.

But really it’s not that much. If you walked outside right now and started running down the street, your body would have to start pulling that glycogen out of the muscles and liver to burn. After a while you’d run out and do what endurance athletes call “bonking.” You’d either have to stop running or you’d have to ingest glucose fast, like by drinking Gatorade or eating a granola bar. Without the extra glucose coming in, you will have expended your glycogen stores up.

Even while sleeping at night, this stored glucose is burned up and our blood sugar drops. When we wake up we break the fast and stuff some donuts back in there.

Here’s the kicker: What happens when the liver and muscles are already full of glycogen? I already said it’s not that much. So it doesn’t take much to fill. If those places are already full, and too much glucose in the blood is dangerous, where the hell does insulin send the extra glucose when you decided to eat the whole bag of chips and three Twinkies in twenty minutes?

The answer is it turns that glucose into fat and sticks it all over the body for later usage. Insulin says “Well, since glycogen stores are full, and we don’t seem to need this energy at this time sitting calmly at our desk, I’ll stuff this in an extra energy storage depot called body fat.”

So when would that fat be used? Not unless the glycogen stores in the body become depleted and there’s nowhere else to get energy. Then the fat starts to burn. The problem is that we eat in a way that keeps our glycogen full. We don’t tap into the fat because the tanks stay full up and there’s no need.

I mentioned earlier that the body can use two macronutrients for fuel: carbohydrates and fat. You can see that fat is basically just the stored form. When you eat a piece of animal fat, that comes from plants they ate. Remember, big fat cows eat grass. They turn the carbohydrate into glucose and store all the extra glucose as fat, as I just explained. When you eat their fat in a piece of meat or dairy, you eat the extra glucose they stored.

When we eat fat we use it for many different things, like building cell membranes and things. The brain is mostly fat. So fat is essential. But as far as energy goes, if we eat glucose a lot, we don’t usually burn fat. If you’re not using the fat on your body, you ain’t really burning the fat you eat.

So how the hell do we get the fat off of us? We have to lower glucose intake so that the body can burn up the stored glycogen and finally get to the fat.

So you can see that I’ve basically made the case for a low-carb diet. There are many variations on this and biochemical complexities that I’ve skimmed over. But the gist is that if there is a constant tap of glucose coming in, and the tub is already full, it will overflow. The first step is to turn of the tap. Eat less carbs.

So if carbs and fats are the only main energy sources, and we eat less carbs, we’ll have to replace it with: GASP! Fat!

Yes, the low-fat era has largely been a marketing campaign by food companies that have loaded their products with sugar. Remember, when you’re at the grocery store and you see anything that says “Low-Fat,” that means it’s high-sugar. Low-Fat equals high-sugar. And if you take the fat out of food, you’d better put lots of sugar in, because fat is very satisfying to taste and very filling. Without fat, things taste flat.

The saturated fat and cardiovascular disease connection is being seriously questioned by research right now. The idea that saturated fat “clogs your arteries” is myth. It doesn’t work like that. I’ll cover this is another piece.

But for now, if eating loads of saturated fat in the form of bacon and butter and coconut oil still scares you, you can replace carbs with “healthy” mono- and polyunsaturated fats like nuts and seeds and other oils.

Fats are also more energy dense than either carbs or protein. Whereas carbs and protein both have four calories per gram, fat has nine. So it has more than twice as much energy in it. You’d need less of it for the same output. It’s a far more efficient source of fuel.

If you eat more fat this way, and grab some almonds instead of chips, you’ll allow your body to burn off the glucose and you’ll move it more toward a fat-burning, rather than a glucose-burning, metabolism.

If your pantry is full of carbs, and you’re lost, don’t fret: eliminating simple sugars like candies and sodas are step one. Remember the tub analogy: you can have these things sometimes, but just be mindful that you’ll be filling the tub back up if you do too much.

The paleo diet is the easiest way to move in this direction. Check that out if you haven’t. Some people do better with a bit more carbs than others. So you can tinker.

The strong end is nutritional ketosis, which is a fat-burning state where carbs are eliminated to near-zero and the diet is mostly fat. Carbs are actually not necessary to survive. Fat and protein are. The body can still make the little glucose it needs from other things.

And rather than making you fat, eating a ton of fat makes one a fat burning machine, and then fat on the body is used when one is not eating.

Unlike glycogen, which burns out rather fast, the fat on even a skinny person’s body can usually provide months of calories without eating food. There is an evolutionary logic behind these two different energy metabolisms.

In nature, glucose was not readily available. The occasional fruits would be the sweetest thing around, and eating a bunch of them would make you a little chubby before winter came, which was when you would go into ketosis to burn off your body fat to survive, and you’d get lean again.

The problem is we now have convenient stores with thousands of calories of glucose at our fingertips and it never stops. Switch it up and eat some real food with moderate amounts of carbs, proteins and fats. By the way, when you do have carbs, eating protein and fat with it can slow down that glucose and insulin spike, so the whole things goes over more smoothly.

Don’t try to eat less calories for the sake of it, or let yourself go hungry, in order to lose weight. That’s not healthy, and diets don’t work because people deprive themselves too much and they binge. They also try to exercise too much and wear themselves down.

The first step to losing weight is not training for a marathon. You don’t have to run another step in your life to lose weight. Food is energy and makes the bigger difference. Like I said, exercise just helps, but not if your diet sucks. Better to eat a burger without the bun than to run around the block ten times and come back to eat a big bowl of spaghetti with garlic bread.

Make some small healthy swaps first and eat until you’re full and satisfied. Just try to eat differently. It’s no magic bullet. And there are ALWAYS mishaps and too many cinnamon rolls gorged by accident. But over the long haul, shifting things around can work.