Ever wandered down the "health foods" aisle of your local grocery store?
If it's anything like the one near me, it's full of low-fat, carb-heavy snack foods.
Here's the problem: Low-fat diets don't work.
Years of research have shown this to be the case. An eight-year trial involving almost 50,000 women, roughly half of whom went on a low-fat diet, found that those on the low-fat plan didn't lower their risk of breast cancer, colorectal cancer, or heart disease. Plus, they didn't lose much weight, if any.
But less research has focused on what would happen if we took out the calories that we were getting from specific types of fat and swapped them with calories from carbs — or, more intriguing, with calories from other types of fat.
That's where a new study, published this month in the Journal of the American Medical Association, comes in. Its research suggests that sugar — not fat — could be the problem.
This isn't surprising. Decades of research have suggested that sugar is the real culprit when it comes to weight gain, since in high amounts (and when not balanced with protein and fat, which the body breaks down more slowly) it can lead to dramatic increases and drops in blood sugar. These "crashes" can cause "hanger", or what's known as being angry and hungry at the same time.
All carbohydrates — bread, cereal, or potatoes — are ultimately broken down into glucose, which circulates in our blood and gives us energy. Sugars get broken down quickly and tend to raise blood glucose most dramatically. And, according to the Centers for Disease Control and Prevention, most of the calories that Americans are getting from sugar are coming from processed foods like cereals, granola bars, breads, and cakes.
Still, 'not all fats are created equal'
For the latest paper, the researchers looked at the eating habits of more than 126,000 people who submitted health questionnaires every few years for up to three decades. Next, the authors tested what would happen if those people swapped out 5% of the calories in their diets from saturated fat (the types of fats most often found in meat and dairy products) with one of three other things: A) calories from simple carbohydrates like sugars and refined grains; B) calories from monounsaturated fats, like the kind found in avocados and olive oil; or C) calories from polyunsaturated fats, like the kind found in oily fish and nuts.
Not surprisingly, the first option — replacing the calories from saturated fats with calories from simple carbs — was not linked with any health benefits that they could observe.