Only Calories Matter Study Claims

[liv]

I assume you guys have heard or read about this study. It was just published and is getting plenty of press

NEJM -- Comparison of Weight-Loss Diets with Different Compositions of Fat, Protein, and Carbohydrates

Comparison of Weight-Loss Diets with Different Compositions of Fat, Protein, and Carbohydrates

Frank M. Sacks, M.D., George A. Bray, M.D., Vincent J. Carey, Ph.D., Steven R. Smith, M.D., Donna H. Ryan, M.D., Stephen D. Anton, Ph.D., Katherine McManus, M.S., R.D., Catherine M. Champagne, Ph.D., Louise M. Bishop, M.S., R.D., Nancy Laranjo, B.A., Meryl S. Leboff, M.D., Jennifer C. Rood, Ph.D., Lilian de Jonge, Ph.D., Frank L. Greenway, M.D., Catherine M. Loria, Ph.D., Eva Obarzanek, Ph.D., and Donald A. Williamson, Ph.D.

ABSTRACT Background The possible advantage for weight loss of a diet that emphasizes protein, fat, or carbohydrates has not been established, and there are few studies that extend beyond 1 year.
Methods We randomly assigned 811 overweight adults to one of four diets; the targeted percentages of energy derived from fat, protein, and carbohydrates in the four diets were 20, 15, and 65%; 20, 25, and 55%; 40, 15, and 45%; and 40, 25, and 35%. The diets consisted of similar foods and met guidelines for cardiovascular health. The participants were offered group and individual instructional sessions for 2 years. The primary outcome was the change in body weight after 2 years in two-by-two factorial comparisons of low fat versus high fat and average protein versus high protein and in the comparison of highest and lowest carbohydrate content.
Results At 6 months, participants assigned to each diet had lost an average of 6 kg, which represented 7% of their initial weight; they began to regain weight after 12 months. By 2 years, weight loss remained similar in those who were assigned to a diet with 15% protein and those assigned to a diet with 25% protein (3.0 and 3.6 kg, respectively); in those assigned to a diet with 20% fat and those assigned to a diet with 40% fat (3.3 kg for both groups); and in those assigned to a diet with 65% carbohydrates and those assigned to a diet with 35% carbohydrates (2.9 and 3.4 kg, respectively) (P>0.20 for all comparisons). Among the 80% of participants who completed the trial, the average weight loss was 4 kg; 14 to 15% of the participants had a reduction of at least 10% of their initial body weight. Satiety, hunger, satisfaction with the diet, and attendance at group sessions were similar for all diets; attendance was strongly associated with weight loss (0.2 kg per session attended). The diets improved lipid-related risk factors and fasting insulin levels.
Conclusions Reduced-calorie diets result in clinically meaningful weight loss regardless of which macronutrients they emphasize

Some info about the research

Other goals for all groups were that the diets should include 8% or less of saturated fat, at least 20 g of dietary fiber per day, and 150 mg or less of cholesterol per 1000 kcal. Carbohydrate-rich foods with a low glycemic index were recommended in each diet. Each participant's caloric prescription represented a deficit of 750 kcal per day from baseline, as calculated from the person's resting energy expenditure and activity level.

I think this one will be used a lot to attempt to debunk low carb diets.

[Georgiana]

Re: Only Calories Matter Study Claims

I think this one will be used a lot to attempt to debunk low carb diets.

I believe you're right, Liv. And since most people take for granted whatever the media is trying to sell them, without actually reading the study, I am wondering how many will be put off from starting Atkins (or convinced to switch diets, for that matter) because of these results. I start to sound like Jimmy Moore, but in a world where so many people are already confused as to whether they should follow Atkins, WW, South Beach, Zone, Ornish, etc., releasing this kind of information without thoroughly explaining the actual meaning of the results only contributes to increasing obesity rates. If people are told that "all calories are created equal", they will just jump back and forth between different diets and, even if they managed to lose some weight, they would probably fail to keep it off because their eating habits will still be the same and they will know nothing more about their bodies than on the day they began dieting.

Those who have been following Atkins for a while probably know already what I will explain below, but I want to point out a few things for those new ADBB members who, after reading about this study in the news, might consider going off Atkins because of a bad weigh-in day or just because they are missing Pringles.

During (most part of) the weight loss phases of Atkins, one is in ketosis (lipolysis). This means that the body is breaking down lipids (fat) for energy, instead of glucose (sugar) as it would on a "standard" diet. Besides subsiding hunger or increasing energy levels, lipolysis also offers what Dr. Atkins calls a "metabolic advantage". Breaking down fat requires more energy than breaking down sugars, so once you are in ketosis, your BMR (Basal Metabolic Rate) automatically increases. Therefore, eating 1500 calories on a diet that does not involve ketosis leads to a smaller caloric deficit than eating 1500 calories on, for example, Atkins. So, in simple terms, assuming two people would lose weight at the same rate when following the same diet, if you put one on Atkins and the other on, let's say, a low-fat diet, the one following Atkins will lose more in the same amount of time by eating the exact same amount of calories. As I've said, the main reason for this is lipolysis.

Now let's look at the study. The four diets analyzed were:

• (LFAP) low-fat, average-protein: 20% fat, 15% protein, 65% carbohydrate;
• (LFHP) low-fat, high-protein: 20% fat, 25% protein, 55% carbohydrate;
• (HFAP) high-fat, average-protein: 40% fat, 15% protein, 45% carbohydrate;
• (HFHP) high-fat, high-protein: 40% fat, 25% protein, 35% carbohydrate.

Among these diets, the closest to Atkins is the HFHP diet. However, for this diet to create a metabolic advantage (as Atkins does), it should allow one to achieve ketosis.

One way to see whether this happens is to look at the so-called "ketogenic ratio". This is defined as:

0.9*(grams of fat) + 0.46*(grams of protein)
KR = --------------------------------------------------------------------------------------------------
1.0*(grams of carbohydrate) + 0.1*(grams of fat) + 0.58*(grams of protein)

It is considered impossible to achieve ketosis if KR is below approximately 1.5. After ketosis is achieved though, it is possible to remain in ketosis even by eating below a KR of 1.5. Now here comes the beauty of Atkins when compared to the HFHP diet.

In the study, those following the HFHP diet ate the same ratio of macronutrients (fat, protein, carbs) every day. Let's say one ate 1500 calories. Then 40% fat, 25% protein and 35% carbohydrate, are equivalent to approximately 67 g fat, 94 g protein and 131 g carbohydrate. If you plug in the numbers in the equation above, you should get KR=0.54. Since this is much lower than 1.5, none of the participants was actually in ketosis. Their bodies were still burning glucose for energy, hence they gained no metabolic advantage from following a HFHP diet rather than any of the other diets analyzed.

Now back to Atkins. Its first phase is induction, whose main purpose is to induce ketosis. This is done by eating approximately 65% fat, 5% carbohydrate and 30% protein (the percentages being of the total caloric intake). If one were to eat 1500 calories on induction, the macronutrient distribution would be 108 g fat, 19 g carbohydrate and 113 g protein. The ketogenic ratio would then be KR=1.6. Since it is above 1.5, eating this way for a few days should allow one to achieve ketosis and therefore gain a metabolic advantage.

So as long as one keeps his/her body into sugar-burning mode, as it was the case in the study published in NEMJ, I am not very surprised by the equal weight loss rates. But of course, none of this will be mentioned by those criticizing Atkins.

[theredhead]

Re: Only Calories Matter Study Claims

Georgiana, you've given an excellent interpretation of this study.

Here's Dr. Michael Eades' take on it (he's the co-author of Protein Power):

Last gasp of the dark ages of nutrition | The Blog of Michael R. Eades, M.D.

[liv]

Re: Only Calories Matter Study Claims

That is so right on Georgiana. It is absolutely horrible to see how media (newspapers and TV) just repeat the conclusions from studies like that without using any kind of critical sense. (Now I find it a bit disconcerting that this scientist could come to this conclusion without really testing what he claims to be debunking too. The reduction in macro nutrients were not sufficient to draw this kind of conclusion in my opinion)

And it is interesting to note that though all participants in the study ate what they called "low gycemic index food"
the people on HighFat-HighProtein ate things like bagels, potatoes, milk, raisins, banana.

Thanks for the link to the Eades blog theredhead.

There was cool study done by Eric Westman just before Christmas that showed that low carbohydrate food helped control type 2 diabetes. This one did not get that much press. The journalists just seems to ahve a slight bias here.
Link to the Westman study

http://www.nutritionandmetabolism.com/content/pdf/1743-7075-5-36.pdf

[Georgiana]

Re: Only Calories Matter Study Claims

Unless one *searches* for research done on LC diets, almost everything that is presented by the media is on low-fat. I don't know if their attitude is intentionally biased though. It might be just the backfire of years of indoctrination media itself has delivered.

Thanks for the link to the article Liv, I'll have to take a look over it tonight.

Laurie, this statement in Dr. Eades' article is oh so true:

The researchers, old-school low-fatters one and all, constructed the study in such a way as to ensure the outcome they wanted, which was that all that really counted was the total caloric intake.

I see this happening incredibly often in academia -- there is these "old-school" researchers (and their slaves, a.k.a. PhD students ) who cling to theories that were considered to be the "absolute truth" when they started working in the field and, although new research contradicts their theories, they have the influence and connections (esp. with the media) to keep promoting them. It's frustrating, especially when you think of the amount of money that goes into these studies. Hmm... someone press my "Vent OFF" button. I'm really going off topic here.