February 26, 2009

In The News: Oh, Look... Calories!

CNN is reporting the findings of a new study published in the New England Journal of Medicine comparing the efficacy of four diets -- high-carb, low-carb, high-fat, and high-protein.

Although not based on popular diets (the high-protein diet, for instance, does not provide the same distribution of nutrients as Atkins), the four eating plans had their particular distinctions (i.e: one offered 35 percent of calories from protein, while another increased the amount to 65 percent of calories from protein).

The conclusion? "All produced weight loss and improvements in lipids [as well as] reduction in insulin. The key really is that it's calories, not the content of fat or carbohydrates -- just calories," summarizes study co-author Dr. Frank Sacks of the Harvard School of Public Health.

Or, as the study itself beautifully encapsulates it: "reduced-calorie diets result in clinically meaningful weight loss regardless of which macronutrients they emphasize."

No matter which of the four diets the 811 overweight participants were on, they all "had a[n average] 750-calorie reduction per day."

Not surprisingly, they all lost weight.

Note that even the higher-in-fat diets followed American Heart Association guidelines (mainly sufficient fiber intakes and limited saturated and trans fat intake).

Let this be even further proof to the "saturated fat is the healthiest fat; everyone is lying to you!" camp that diets rich in polyunsaturated and monounsaturated fat do indeed lead to improved lipid profiles and weight loss.

Adding to the uniqueness of this study is that it is one of the few that tracked participants on these diets for two entire years.

How will "calories don't matter, it's all about limiting carbohydrates"enthusiasts explain yet another study showing weight loss can be accomplished while eating a substantial amount of carbohydrates?


Anonymous said...

Makes sense to me, and all my diets failed trying to use weird food (especially low fat-what a disaster). Now, I lose weight by eating less and better (said the girl who had 2 cold Vietnamese shrimp roll, two thin mints, and a grapefruit for dinner last night)

Anonymous said...

Any reasonable person must surely agree that reducing calories will result in weight loss, regardless of food mix.

This article in the same issue of the NEJM states that
"That difference [in calories from carbohydrates] turned out to be 6% of energy instead of the planned 30%."
"Protein intake was intended to differ by 10% of energy between the high-protein-diet group and the average-protein-diet group, but the actual difference, as assessed by the measurement of urinary nitrogen excretion, was 1 to 2% of energy "

It's worth noting that even with these very minor differences in caloric intake, the high-fat/high-protein group showed the most improvement in their LDL/HDL profile.

This was a high-fat/high protein diet in which, by study protocols, the dieters had a bagel for breakfast, spaghetti and a banana for lunch, and a potato for dinner. See the actual menu here:
(page 8)

If even a small improvement in calories from fat/protein resulted in the LDL/HDL benefit, think what a more pronounced improvement might do!

Andy Bellatti said...

You are missing out on the point of the study, which is that no one diet was the "clear cut winner."

Consider this:

"At 2 years, the two low-fat diets and the highest-carbohydrate diet decreased low-density lipoprotein cholesterol levels more than did the high-fat diets or the lowest-carbohydrate diet."

Reminder: LDL is the cholesterol you want to lower, while HDL is the cholesterol you want to increase.

So, no, the high-fat diet was not the one showing the most improvement in LDL levels.

However, "All the diets except the one with the highest carbohydrate content decreased fasting serum insulin levels by 6 to 12%; the decrease was larger with the high-protein diet than with the average-protein diet."

As for your comment that "any reasonable person must surely agree that reducing calories will result in weight loss, regardless of food mix," you'd be surprised at how many people are convinced calorie balance is all "a big myth and conspiracy."