Low Fat vs. Low Carb: The low-down on carbs

Recently, the news has been awash with headlines touting the superiority of low-carb diets over low-fat diets in reducing risk factors for heart disease. The implied conclusion: stop eating those oats and vegetables and bring on the fried chicken!

Nothing could be further from the truth. Health depends on consuming a wide variety of macro and micro nutrients. Focusing only on the “macros” of food (carbohydrates, fats, protein) simplifies nutrition to a ridiculous level. It’s not about low fat or low carb. It’s about smart fat and smart carb.

Not all carbs are created equal. Froot Loops® and bagels are carbohydrates and so are oats and blueberries. But when you eat Froot Loops® and bagels, the biochemical consequences are very different than when you eat oats and blueberries.

Froot Loops® and bagels are highly processed, simple carbohydrates. When you eat them, they digest quickly and absorb rapidly — as sugar. When sugar levels spike in our blood, our insulin levels go up. Insulin’s main action is to store the blood sugar floating around. 

But when you trigger insulin, it doesn’t just store sugar, it shifts our entire biochemistry into storage mode. The storage form of cholesterol is LDL — the bad cholesterol. So when insulin levels are higher, LDL levels go UP. The non-storage form of cholesterol is HDL — the good cholesterol. When insulin levels are high, HDL goes DOWN.

Some of the worst cholesterol profiles appear in people following a low fat/high carb diet. But that’s not because their diets are low in fat, it’s because they include a lot of simple, highly processed carbohydrates.

Complex, unprocessed carbohydrates — like oats, flax, chia and blueberries — are full of fiber and are difficult to digest. This means they digest slowly and absorb slowly, resulting in much lower insulin levels. Low insulin levels lead to the opposite in cholesterol profiles – lower LDL and higher HDL. The fiber in these foods has the added benefit of trapping cholesterol in the gut, leading to even lower cholesterol levels.

So don’t fall for the low carb headlines. People who did better on low carb diets didn’t do better because they ate fewer carbs. They did better because they ate fewer PROCESSED carbs.

The take away?

First, all carbohydrates are NOT created equal. The less processed and closer to its natural form, the better the carb. Eating an apple is better than drinking a glass of apple juice. Eating a bowl of oatmeal is better than eating a bagel made with a bit of oat flour.

Second, important nutrients — including fiber and antioxidants — only come from complex carbohydrates like whole grains, vegetables and fruits.