There have been dozens of studies—and numerous meta-analyses—pitting the two approaches against one another. They’ve been evaluated not just for weight loss but other measures of health such as cholesterol, blood sugar, blood pressure, and body composition, as well. Each “side” has some put some points on the board but neither one of them is running away with the game.
Comparing Apples to Apple Jacks
Part of the problem is that the terms low-fat and low-carb are used somewhat indiscriminately. Diets described as low-carb in the medical literature might get as little as 10% of calories from carbohydrates or as much as 35% of calories. The same goes for “low fat” diets. But an even bigger problem is that categorizing diets simply by how much carbohydrate or fat they contain is like trying to categorize novels simply by how many nouns and verbs they contain.
You can follow a low carbohydrate diet and eat bacon-cheeseburgers (without the bun, of course) every night for dinner or your low carb menu could feature grilled salmon and avocado. You might be getting most of your non-carbohydrate calories from fat or you might be eating lots of protein. Who could say?
Similarly, on a low fat diet, you could start every day with sugary breakfast cereal (topped with skim milk, of course) or you could sit down to steel cut oats and fresh berries for breakfast. You might be getting very little protein or quite a bit. These uncontrolled variables could have a significant impact on things like blood chemistry and fat loss, not to mention your appetite, digestion and energy.
Same Foods, Different Proportions
That’s why I was so intrigued to read about a recent study that compared a diet that was low in carbs and high in fat with a more balanced diet—while controlling for many of these other variables. In this study, which involved 44 overweight men, the participants ate more or less the same foods but in different proportions.
One group held carbohydrates to just 10% of calories while the other group ate slightly more than half their calories from carbohydrates. However, both groups were instructed to completely avoid added sugars, refined carbohydrates, and processed foods. Protein consumption was held constant between the two groups, as was the amount of omega-6 and omega-3 fats in the diet. Although the low carb group ate a lot more fat than the balanced diet group, both were getting their fats from the same foods: butter, cheese, meat, and eggs. Finally, both groups ate around pound of vegetables a day. (Be still, my beating heart!)
In other words, despite significant differences in carbohydrate and fat intake, both groups were eating a diet of minimally-processed whole foods. And after 12 weeks, both groups posted similar results in terms of weight and fat loss.
Forget High and Low. Go Whole
In other words, you don’t necessarily have to give up carbs (or fat) to lose weight and improve other health indicators. Just give up the junk food. Of course, you’ll also have to eat fewer calories if you want to see a change on the scale. But you may find that replacing highly processed foods with whole foods ends up reducing your calorie intake automatically—and relatively painlessly.
A recent study found that Americans on average get more than half their calories from “ultra-processed foods,” meaning ready-to-eat meals and snacks, convenience foods, and beverages—accounting for about 1,200 calories and about 65 grams of added sugar per day. If you were to replace most or all of those chips, fries, sweets, fast foods, and soft drinks with whole or minimally processed foods, I bet you’d have a very hard time getting it to add up to anywhere near 1,200 calories.
If that’s too big a shift to make all at once, start by replacing half the processed food in your diet with whole foods. See what happens.
If that’s too big a shift to make all at once, start by replacing half the processed food in your diet with whole foods.
Paleo Versus Vegetarian?
Just as I was finishing writing this week’s episode, I received an email from Erin, who wrote:
“Is it better for long-term health and weight stabilization to forego meat or to give up carbs? I can't do both. I've tried both vegetarian and paleo and there are communities, specialized foods, and great cookbooks for both lifestyles. But which one pays off more in the long run? I will add that I find it easier to give up meat than to say no to pasta, whole wheat bread, and oatmeal muffins.”
I think either approach can work, Erin. To me, the fact that you’d rather give up meat than whole grains is a strong argument against embracing your inner cave-woman. If you find that identifying with a particular community or lifestyle is helpful or makes it more fun, go for it! But I think it’s also fine to be a vegetarian who occasionally eats meat or to follow a Paleo-ish diet. In my opinion, keeping the emphasis on whole foods and balance is much more important than maintaining strict adherence to either set of rules.
Questions? Comments? Post them below or on the Nutrition Diva Facebook page.
Image courtesy of Shutterstock.
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