What are good carbs and what are bad carbs?

There are too many diets buzzing around today: paleo, Weight Watchers, gluten free, raw food, the zone, south beach, and the list goes on. The problem is, none of them really work because they’re not grounded in real science, instead relying on fads and gimmicks to grab your attention.

That’s why I’m here - I want to help you decipher the science behind effective diets and incorporate it into your everyday life. With the right knowledge and tools at your disposal, you can easily create effective and lasting lifestyle changes all without the gimmicks, programs, enormous time commitments, or calorie counting of typical diets. To start, check out this flow chart of carbs, and I’ll walk through its ‘whys and hows’. By the end, you’ll be able to decipher good carbs from bad and, most importantly, know why. Ready? Let's dive in.

What are carbs?

Carbohydrates make up most of the organic material on the planet. Traditionally the ones that we eat are roughly divided into two categories: simple and complex. Nevertheless, they’re all, more or less, made of the same stuff: glucose. Usually, when we see glucose, most of us think two things: it’s the sole energy source for our cells and its healthy in natural forms; both are common misconceptions. However, it’s an under-recognized fact that glucose and its isomers make up all the carbs we eat. For example, regular, old table sugar (aka sucrose) is made up of one glucose and one fructose (glucose’s more nefarious cousin). On food packets, you’ll see these simple carbs accounted for under the “Sugars” section. Years of nutritional advice have convinced most of us of the evils of sugars (even if we all indulge sometimes). The water gets murkier though when it comes to complex carbs.

Complex carbs are similar to their simpler cousin, sugar, but larger. Much larger. While sucrose only contains one glucose and one fructose, a complex carb like starch contains tens of thousands of glucose molecules all joined together in long chains. Complex carbs are also found everywhere: peas, beans, whole grains, and vegetables. These carbs make up the majority of everything that is non-meat. They’re ubiquitous.

Growing up I remember always being told to avoid simple, sugary carbs and eat complex carbs instead. This advice sounded good, avoid sugars and eat whole, natural foods. There’s only one problem. Not all complex carbs are created equal.

The Tale of Two Carbs: Good Carbs & Bad Carbs

Bad Carbs: Starch

In plants and animals, complex carbs generally function as energy storage and as structural building blocks. Plants store much of their energy as starch. Potatoes are a good example of starch. The part of the potato that we eat is its underground glucose reservoir which it uses during the winter when resources are scarce. Similarly, in grains like wheat, white flour is made from the starch that its seeds use to begin growing. Whole grain flour isn’t much better as it simply includes the outer shell of the seed along with the inner starch thus giving the brown appearance. The body also stores energy in carbs called glycogen. Glycogen is our version of the plant’s starch - we use it for short term energy storage in our muscles.

But wait. What does this have to do with me and my diet again???

Well, predictably, since starch’s purpose is energy storage and releases as needed, starch is digested and absorbed incredibly quickly. And guess what it’s absorbed as? Glucose. So next time you’re munching on a potato, some rice, or your morning corn flakes just imagine it as a giant bowl of sugar… Not so appealing anymore, right?

Ultimately, both simple and starchy carbohydrates are turned to glucose (blood sugar) in the body. For a hardcore athlete, sometimes this isn’t a problem because they’re constantly depleting glycogen reserves, but for the majority of us, our bodies are already saturated with glucose and glycogen (kinda makes you want to hit the gym right?).

So, what happens to all the glucose we eat?

Your handy liver converts it to fat of course. Any unused glucose (most of it) is stored as fat commonly right around your tummy. As if that wasn’t bad enough, the repetitive spikes in our blood glucose levels after carb loaded meals (also called postprandial hyperglycemia if you want sound smart) is linked to more terrifying problems like heart disease, diabetes, cancer, and chronic inflammation, just to name a few. I guess it would be fair to sum these up as Bad Carbs.

Okay, starch=bad, but how do I avoid it?

The best way to avoid starch is to avoid the foods that contain them in high quantities like potatoes, grains, bread, and all junk foods. If you’re not sure if a food has high quantities of starch, you can always find it online, the glycemic index and glycemic load are useful tools to do this, and you can learn more about them here. But, as a rule of thumb, a quick look at the grams of carbohydrate minus the grams of fiber and sugar would give you a rough estimate of the starch content of a food (don’t forget about the sugars though).

Good Carbs: Fiber

But it’s not all bad news. Remember there’s another category of complex carb we eat.

Fiber, the common term for digestion-resistant carbohydrates. Cellulose is a perfect example of fiber, it’s the most important macronutrient of plant-eating animals and the main component of the much lauded 5-a-day serving of vegetables. In nature, fibers like cellulose are used to build the structure of plants, their stems and transportation networks (phloem and xylem for the botanists out there). Interestingly, these carbs are made of the same exact stuff as starch, glucose.

Well, why don’t they cause the same problems as starch then?

Well, it turns out, the enzyme used for digesting complex carbs in humans, and most animals, can’t digest fiber, only starch, and glycogen. Why? That’s a different can of worms which you can read more about here: this link for more information.

Instead of digesting it on our own, beneficial bacteria in our gut break fiber down into products we can gain energy and all sorts of vitamins & nutrients from. It may be odd to think about but all animals, humans included, have evolved over tens of millions of years, to rely on hind gut fermentation for much of their energy needs since starch and sugars were relatively scarce in the natural world. In fact, our symbiotic relationship with these bacteria provide essential nutrients and are vital for normal intestinal health and immune function.

Wait you’re losing me again. So, yeah... fiber is digested slower than starch but how does that help me?

Well, since fiber is digested slowly by the friendly bacteria in our gut. This keeps us fuller longer, promotes a healthy immune system and most importantly, doesn’t contribute to the numerous adverse health effects of excess insulin.

In essence, fiber is the opposite of starch. While starch is rapidly converted into glucose, fiber slows glucose absorption into the body. While starch is effectively considered ‘empty calories’, fiber is converted into vital nutrients that are critical to regulating our body's homeostatic functions, preventing heart disease, improving intestinal health, decreasing inflammation and hunger. So far from being useless, fiber is a crucial nutrient.

So, fibers = Good Carbs.

Good Carb Foods

Instead of eating starchy or sugary foods, replace them with low carb, high fiber foods.

Most fruits and vegetables are high in fiber. Here is a short list of foods high in fiber:

Fruits: avocados, coconuts, raspberries, pears, apples, bananas, oranges, strawberries, figs, and raisins
Grains: barley, quinoa, and oat bran
Legumes: lentils, black beans, kidney beans, lima beans, chickpeas, and baked beans
Nuts and Seeds: almonds, walnuts, pistachio nuts, pecans, flaxseed, chia seeds
Vegetables: all leafy greens, artichoke, okra, squash, green peas, broccoli, turnips, cauliflower and brussel sprouts.

Unsurprisingly, most of the starchy carbs we eat every day come from baked goods like breads, muffins, cakes, and tortillas. Normally, it’s impossible to eat stuff like this and still avoid the weight gain, However, there exists a few low carb, high fiber flour substitutes that will practically eliminate any of your favorite foods adverse effects from excess starchy carbohydrates.

For a more comprehensive low carb, high fiber dietary guidelines he

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