Last week I wrote that it may not be long before the food industry will be proven wrong about their two favorite messages: All calories are created equal, and it's all about personal responsibility. Well, it appears that science may be one step closer to proving at least half of that equation wrong and that in fact; all calories are not created equal. The latest study, published in The Journal of the American Medical Association (JAMA) this week, found that when it came to weight loss and maintaining weight loss, those who ate a low carbohydrate, high fat diet kept more weight off than those who were on either a low glycemic diet or a low fat, high carbohydrate diet.
While all participants in the study ate the same number of calories, the types consumed varied. The low fat diet contained 60 percent carbohydrates, 20 percent protein, and 20 percent fat. The low glycemic diet contained 40 percent carbs, 40 percent fat, and 20 percent protein (with a focus on minimally processed foods). The low carb diet had 10 percent of calories from carbs, 60 percent from fat, and 30 percent from protein.
Compared to those on the low fat diet, those following the low carb diet burned 350 calories more per day and those on the low glycemic diet burned 150 calories more per day.
The most compelling part of this study is that it calls into question the long-held belief in the scientific and medical communities that all calories are created equal. This is a message the food industry has also seized on since it means they can continue to pump out ultra processed nutritionally void foods and tell Americans to "eat them in moderation." If all calories are created equal, the food industry says, then there are no bad foods.
But this message doesn't just come from the food industry -- Marion Nestle, a long-time critic of Big Food, has spoken about calories in a similar way. She wrote on her blog that the JAMA study was too small (it had 21 participants) and that more research was needed outside of a controlled setting. She's quoted in USA Today saying:
Longer studies conducted among people in their own environments, not with such controlled meals, have shown "little difference in weight loss and maintenance between one kind of diet and another." More research is needed to show that interesting results like these are applicable in real life, she says. "In the meantime, if you want to lose weight, eat less."
I disagree. As a nutrition educator, I think that telling people to "eat less" is largely ineffective and continues to place the burden on the consumer as part of the personal responsibility credo. On the other hand, telling people to eliminate processed, refined carbohydrates and sugars, while eating plenty of high quality fats, proteins, and vegetables seems to be a more workable solution to stimulating weight loss. Part of the reason this may be so effective is because simple carbohydrates and sugars actually stimulate appetite and cravings, while fats, proteins, and complex carbohydrates like vegetables, beans, and legumes satiate and stabilize blood sugar.
A recent report put out by the World Public Health Nutrition Association found that processing does matter, noting that ultra processed foods are "habit-forming and some would say often at least quasi-addictive. They do displace healthy meals, dishes and foods and thus are liable to cause obesity or else at least mild malnutrition."
The addictive factor of these foods is highly problematic and there's evidence to suggest that eating sugar makes you crave and consume more sugar starting with our experiences as babies and even in utero (see a recent article on Gilt Taste for more on this).
And according to Robert Lustig, a professor of clinical pediatrics at UC San Francisco, a low carb diet or a low glycemic diet is what helps keep our insulin levels low, he believes that elevated insulin levels are at the root of obesity. "To borrow a phrase from Bill Clinton: It's the insulin, stupid. The reason any diet will work is because it lowers insulin. And a diet that doesn't, like the traditional low-fat diet, won't work," he said in a recent Los Angeles Times article.
Anecdotally, I've noticed that once my clients cut sugar and simple carbohydrates from their diets their cravings for these kinds of foods quickly dissipate. It's only observational, but I see it repeatedly and so do other nutritionists and doctors I know.
Over online at The New York Times, Mark Bittman wrote about the JAMA study with a conclusive evaluation, "The message is pretty simple: unprocessed foods give you a better chance of idealizing your weight -- and your health. Because all calories are not created equal."
But there's still no consensus among doctors, nutritionists, researchers, or writers.
The implications for coming to a scientific consensus about whether or not types of calories do matter cannot be understated since it could effect regulation for Big Food as well as the dietary recommendations from the government which translates to (among other things) what children eat in school every day. Right now, MyPlate recommends that Americans eat an average of 6.3 servings of grains a day. Even the American Diabetes Association recommends a high carbohydrate and low fat diet. But if the results from this latest study are accurate, all of these recommendations may ultimately prove harmful. Acknowledging that all calories are not created equal and that ultra processed foods are detrimental to everyone would go a long way in changing our crash course with diet related disease and death.
A version of this post appeared on Civil Eats