There's been a lot of buzz recently about a new study that punched a few new holes in the already-tattered notion that weight gain and loss is simply a matter of "calories in vs. calories out."
What Did the Study Find?
One big challenge with losing weight is keeping it off after you've lost it. Most people eventually end up regaining most or all of the weight they've lost. So, researchers took people who had recently lost a significant amount of weight and compared the effectiveness of three different maintenance plans:
All three plans had the same number of calories -- precisely calibrated to match the number of calories each person burned each day. Not surprisingly, over the course of the study, no one lost or gained any weight.
The big news was this: People burned, on average, 300 more calories a day when they were eating the very low carb plan than they did on the high-carbohydrate plan. The low-glycemic diet was somewhere in between. The study authors concluded that, over time, people eating a low-fat diet would have a much harder time maintaining their weight loss than people on a lower-carbohydrate regimen.
Unfortunately, the study authors also noticed some negative effects from the very low carbohydrate diet. While on the low-carb regimen, subjects experienced increased levels of stress hormones and inflammation markers -- both of which might increase the risk of obesity over the long term. People on the moderate-carb, low-glycemic diet seemed to fare best of all. They burned extra calories but with none of the negative effects.
As news of the study spread, my inbox filled up with questions from journalists, news directors, medical colleagues, and readers. How significant is this finding? Is this really something new? Will this study change my advice regarding diet and weight loss?
Is This a New Finding?
It's not surprising (to me, anyway) that eating more protein and fewer refined carbohydrates would affect metabolism. (See my article "Protein and Weight Loss.")
I think what's most striking about this study is the magnitude of the effect -- 300 calories a day is a pretty big deal. I suspect that one reason that this study produced such dramatic results is that the subjects had just lost a significant amount of weight in a short period of time. Rapid weight loss produces some very dramatic changes in energy metabolism, and the fact that the subjects were in that exaggerated state of metabolic flux when they started the study may have amplified the effects of the three diets.
I think the effect was further exaggerated by the fact that the high-carbohydrate diet wasn't just high in carbs, it was high in refined carbohydrates -- foods that send blood sugar soaring and trigger big rushes of insulin, a hormone that promotes fat storage. And while there are still a few die-hards out there promoting a low-fat, high-carb diet, none of them are recommending that you load up on refined carbohydrates. Had the high-carbohydrate portion of the trial used the same low-glycemic foods as the moderate-carbohydrate diet (just more of them), I'm not sure the difference between those diets would have been as large.
Furthermore, if the moderate-carbohydrate diet had been as high in protein as the low-carbohydrate diet, it might have closed up the gaps even further. Finally, both the moderate- and low-carbohydrate diets featured a much higher proportion of monounsaturated fats -- which have been found to promote fat oxidation and weight loss. Had all three diets used the same types of fats, the differences might not have been as dramatic.
In other words, there were a lot of differences between the diets besides just the quantity of carbs.
It also must be said that the study was too small and too short to be considered the final word on the subject. But it certainly got everyone's attention!
Do Calories Still Matter?
"Carbs, not calories, lead to weight gain," blurbed the New York Times. But, as a take-home message, that's a little misleading. The study didn't find that you could eat as many calories as you want without gaining weight, as long as none of them are carbs. Remember, the amount of calories consumed by the dieters was strictly controlled to ensure weight maintenance. It's just that they got to eat a bit more when they backed off the refined carbs -- without gaining weight.
So, here's my slightly more nuanced take-home lesson:
Excess calories still lead to weight gain -- but excess calories from refined carbohydrates will do it faster than calories from other sources. In other words, all calories matter but some calories matter more than others.
At the end of the day, however, most of us don't have scientists measuring our metabolic rate and precisely calibrating our meals for us. And as the researchers pointed out (but the media largely ignored), identifying the ideal mix of carbs, fats, and proteins is only one part of the puzzle.
"A strategy to reduce glycemic load rather than dietary fat may be advantageous," they wrote. "[But] ultimately, successful weight loss maintenance will require behavioral and environmental interventions."
Does This Change My Advice?
So, how does this research translate into the real world? Does it change my previous advice? Not really. Here, by way of review, are the basic tenets of my approach -- all of which are in line with these new findings:
For more by Monica Reinagel, MS, LDN, CNS, click here.
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David Katz, M.D.: The K-E Diet: Weight Loss Lunacy
Dr. Jade Teta: Want to Lose Fat? Count Your Hormones, Not Your Calories (Part 2)
Kristin Wartman: A Calorie, Is a Calorie, Is a Calorie -- Or Is It?
Jeanette Pavini: Diets on a Dime -- What You Should Know
-Kelsey @ www.zinganything.com
I lost a lot of weight on my own plan which is based on the texture, coldness, amount of processing of food I ate. Coha Diet.
I had a .9 lb ribeye (shared with my wife, let's say 60/40 me/her) with plenty of veggies (cooked in coconut oil) the other night.
No way I could have breakfast (especially my usual breakfast of 3 eggs and 3 slices of bacon). I actually got hungry at around 1:30pm, barely hungry (I ate a small salad).
The fact is, a calorie is a calorie. The biggest issue is that not every calorie carries the same weight of nutrients as the next. Your nutrient intake is far more important that your calorie intake.
Pick up a textbook. It's the only printed medium that actually has any standards applied to it.
For the TRUTH and a brilliant analysis:
http://eatingacademy.com/books-and-articles/good-science-bad-interpretation
From the study itself:
"Although the very low-carb diet produced the greatest improvements in most metabolic syndrom components...we identified 2 potentially deleterious effects of this diet. Twenty-four hour urinary cortisol excretion, a hormonal measure of stress, was highest with the very low carb diet...Higher cortisol levels may promote adiposity, insulin resistance, and carbiovascular disease, as observed in epidemiological studies."
While there was a slightly higher level of CRP with the VLC diet, it was well within normal healthy ranges - Medline Plus states that "You are at low risk of developing cardiovascular disease if your hs-CRP level is lower than 1.0mg/L." VLC had a CRP of 0.87 CRP, Low GI was 0.76, and Low fat 0.78 so they were all in very healthy, low risk ranges for CHD so CRP is largely unimportant (at least a 1 month).
Also, no one seems to consider that VLC also led to much BETTER insulin resistance outcomes than the other diets (higher HDL, lower triglycerides, as well as higher peripheral and hepatic insulin sensitivity). Insulin resistance is thought to be the potential underlying cause of diabetes, hypertension, heart disease, cancer, Alzheimer's, etc. Therefore, isn't this latter finding just as supportive of VLC being healthy than the huge metabolic benefit (~350 extra calories burned/day without exercise) and "low risk" CRP?
Thanks, Monica. Would appreciate your thoughts.
You stated: “Remember, the amount of calories consumed by the dieters was strictly controlled to ensure weight maintenance. It's just that they got to eat a bit more when they backed off the refined carbs -- without gaining weight.” But they didn’t “eat a bit more;” … “the amount of calories consumed by the dieters was strictly controlled.” Yet low carb dieters didn’t lose more weight than low fat dieters. Why not? http://caloriesproper.com/?p=1653