Editorial: Should we going back to calorie-counting?
Here we go again. The prestigious New England Journal of Medicine recently published a comparison study of weight-loss diets that seems sure to shake up the Conventional Wisdom of weight loss one more time. Many of the major news services covered this report since its conclusions upend the popularly-held belief in a high-protein (or practically any other type of weight-loss) diet. Instead, the putatively surprising finding of this study was that it didn’t matter whether protein, carbs or fats were high or low; long-term weight loss success came down to simply calories-in versus calories out. That is to say, manipulating protein fat and carb levels didn’t matter, what mattered was reducing overall calorie intake. So what does this mean to the millions of people trying to lose weight? Is it time to rethink the high-protein low-carb approach?
We read this report and its news coverage with great interest since weight-loss is such an important issue to so many of our customers, some of whom have already written in to ask our interpretation of this report.
Thousands of our customers are years into a high-protein low-carb approach to weight-loss with varying degrees of success. It’s easily the most popular approach from our vantage point.
On the product side, there are hundreds of products that simply wouldn’t exist had the high-protein low-carb approach never become as massively popular as it is. And it’s hard to see how it could achieve and sustain such popularity without delivering real-world benefits for its practitioners.
It’s great when the mainstream media reports on news related to nutritional science and improving health. The more good information that gets out there the better. But it’s dismaying to see how consistently news outlets simultaneously oversimplify and sensationalize such stories. Stories about diet. Stores about weight-loss. Stories about vitamins and nutritional supplements. Most of the reporting we’ve seen that relates to this story emphasizes, in particular, that high-protein diets are no better than any other kind of macronutrient-manipulation.
Before anyone abandons their current approach and reverts to simple calorie-counting, take a moment to read a brief abstract that appears at the beginning of the NEJM weight loss study, or the whole report itself.
What do you think? At face value, it’s conclusion of the report isn’t a terribly bold statement:
“Reduced-calorie diets result in clinically meaningful weight loss regardless of which macronutrients they emphasize.”
In fact it doesn’t even seem like news; it’s been well-established that by cutting calories you lose weight, all other things being equal.
But there’s an awful lot that this study didn’t take into account. So while it’s an interesting study, there are real limits on what we can infer from it. It’s not as though calories don’t matter – they do – but by being focused strictly on overall weight-loss or gain over a period of time, the study’s field-of-view is too narrow to generate useful conclusions about weight-loss diets one way or another.
For one thing, many people no longer define successful weight loss as simply generating a lower number when they step on the scale. That’s how the study’s designer’s defined it, and that’s how some people define it, but that’s not how we define it, nor do many of our customers.
Weight-loss does not equal fat loss
When people use the term ‘weight-loss’ they invariably mean fat loss. People ‘say’ they want to lose weight, but of course what they mean to say is that they want to lose fat. Is there a difference? There’s a big difference!
Ideally, we’d all prefer that 100% of the weight lost during a diet and exercise program results from a loss of body fat only, not as a result of losing lean body mass (muscle mass, fluids, bone density, all of the non-fat portion of your body). Having 100% of your weight loss occur as a result of only fat loss would be extremely difficult to achieve, though.
So people try to influence that ratio as much as possible by, not just dieting, but also by maintaining or increasing lean body mass through weight training and consuming plenty of protein so muscle is not cannibalized for energy needs. Lean body mass is highly desirable from a fat loss point of view, the more the better.
Many people understand this, which why their weight-loss fat loss program includes lots of dedicated weightlifting and strength training.
Lean body mass weighs much more than fat
Many people also understand that lean body mass weight substantially more than body fat. So as you’re losing body fat and building/maintaining lean body mass – getting leaner, in other words – your actual weight may not change that much. Over a short span of time, it may not change at all even though your becoming physiologically leaner in terms of reducing your body fat percentage.
The only way to track this change in body composition (how much of your body is comprised of fat versus how much is lean mass) is measure it to establish a baseline and then do regular follow up.
Study did not measure or track body composition
Measuring body composition was one of the major flaws of this study. Simply tracking weight changes, while not useless, doesn’t tell us what we think is the most important pieces of information when evaluating a weight-loss approach; how much actual fat loss occurred? How much did body composition change or not?
Study did not take exercise into account
Granted, changing this study to take exercise into account would essentially mean a completely different study from the ground up, but exercise seems entirely too important to omit completely, as this study did. Most people who need to lean up need to change their exercise habits. Many of these people are doing so as they diet. Those who are changing their exercise habits also change their caloric and nutritional needs in the process, and the more intensely they train, the greater this change. They way people exercise can changes over time, too. But simply ignoring exercise altogether to simplify a comparison of weight-loss diets doesn’t make sense since with few exceptions, these are people who should be, or are already, changing their exercise habits. That undermines any conclusions you’d otherwise draw from the information gathered about diet.
We’re not abandoning our advocacy of the high-protein low-carb diet just yet. And we don’t advise anyone to stop paying attention to macronutrients like carbs, protein or fiber. That’s because our customers define weight-loss success much more broadly than is reflected in this study. They don’t want to simply see a smaller number on the scale. They want to change their bodies, and change their lives, and feel better as a result of both. They want to be leaner and stronger and healthier. What works for most people, is a high-protein low-carb diet coupled with a well-designed program of regular exercise. There may be other ways to get there, too, but putting on calorie-counting blinders isn’t one of them.