Monday, March 12, 2007

The Newest Diet Study - What does it really tell us?

By now, you have probably heard about the latest study – You know the one that “proves” that the Atkins diet is superior for weight loss?

So let me just clear this up right now. The results of this study prove one thing and one thing only – diets work.

In fact, after reviewing this study, and all of the commentary, posturing, crying and bickering that it has caused, I have come to the conclusion that this study proves that the very best thing you can do for weight loss is:

Eat less, but enjoy the foods you eat. Eat lots of fruits and vegetables, and lots of herbs and spices. And maybe most importantly, spend less time stressing over the types of food you are eating

In other words - Cut your calories in a way that works for you. ( It might take a bit of trial and error, but it will be worth it.)

Now here are the facts from the study…

311 overweight, pre-menopausal women were divided into four groups and were asked to follow one of the following dietary programs: The Atkins diet, the Zone diet, the LEARN diet or the Ornish diet.

Each woman was put in one of these groups and received a copy of one of the popular weight loss books. Each woman then met with a registered dietitian once per week for 8 weeks learning “the ins and outs” of their assigned diet.

After these classes the subjects were “set free” to follow the diet for 12 months, with the exception of a couple of visits to the lab and some unannounced phone calls where the researchers asked the subjects to recall what they had eaten in the last 24 hours.

What happened?

As expected, all 4 groups ate fewer calories during the study than they were eating before the study – so all diets “worked” to help cut calories.

And each group lost weight with most weight loss happening in the first 2 months. (After this point for all diets, the weight loss tended to slow or even creep back up).

The Atkins style diet had the best weight loss during the first 2 months and over the 6-month study. That’s why you see Atkins being crowned the king of weight loss diets.

However, by end of the 12-month study, the results tended to “even out”. And by the end of the study, the Atkins diet was really only better than the Zone Diet (which isn’t a bad diet on it’s own).

And you know what? The total weight loss wasn’t that impressive – with the Atkins dieters losing 12.5 lbs in 6 months. That’s 0.5 lbs per week. Good, but not eye-popping results.

But here’s the kicker. It’s hard for me to understand how overweight woman (averaging 180 pounds and over 40% bodyfat) can eat less than 1400 calories per day for 6-months and lose only lose 12 and a half pounds. There is something very wrong here.

Looking at the data, I noticed that all of the diets saw a small slow increase in their calorie intake over the year. And honestly, this was probably due to huge errors in dietary recall. Most people can’t accurately describe what they had for lunch, so this measure isn’t worth the paper it was written on.

Dietary recall is a scientific method for measuring caloric intake that has been under a large amount of scrutiny in the past years.

Imagine having someone call you on the phone and ask you to describe all of the foods you had eaten over the day. Imagine the types of mistakes in sizes and types of food that could be made in this type of interpretation and then imagine the kind of effects that this could have in a scientific study.

Now also imagine that you SIGNED UP for a weight loss study, so you are already motivated to eat less and you are also insecure about the amounts and types of food you eat.

For true research, diet recalls are a horrible tool. Plain and simple.

I also noticed that none of the diets were true to their form.

Take a look at the “high protein Atkins style diet”. After 2 months the subjects reported a protein intake of 95 grams. But at 12 months it was down to 82 grams. How is this high protein? It’s not even 0.5 grams per pound of bodyweight!

And check out the “Ornish Low fat diet”. At 2 months fat made up 21% of their caloric intake, at 12 months it made up 29.8% of their calories. This is a far cry from the 10% that Dr. Ornish advocates.

Because the subjects had such a hard time sticking to the diet plans, I don’t think that this trial proved that any one diet was better than the other. It did prove that the diet with the lowest carbohydrates had the quickest weight loss. And it did show that diets high in fat can still have health benefits. Most likely, the health benefits are the result of the reduced calories and the associated weight loss as all the diets were associated with health improvements.

Of course, proponents of each diet are all crying foul. They’re complaining about the study design, the subjects, the poor compliance to the diet plans…but most importantly they’re complaining because they make money by selling you their programs!

Its funny…Dr. Ornish said that the study was flawed because most participants couldn’t follow the Ornish diet. That doesn’t make the study flawed - its makes the diet flawed.

And that’s exactly what this study proves…it is very difficult to follow these prescribed diets. These people don’t know you. They don’t know what you like to eat or what you do for a living. They simply design a diet that makes a lot of sense on paper, and prescribe it as a cure all.

The bottom line is…this study still not help end the debate over which diet works best because there IS NO DEBATE. Eating less works! End of story. The rest of it is just people making simple diet advice into confusing pseudo-science so they can sell you their programs.

Eat less, but enjoy the foods you eat. Eat lots of fruits and vegetables, and lots of herbs and spices. And maybe most importantly, spend less time stressing over the types of food you are eating.


Stumble Upon Toolbar


billy said...

Dude, did you delete my comment? Ouch.

Brad Pilon said...

Hi Billy,

I haven't received any comments on this post yet.

If you posted before, could you please try and repost it.

(I promise I didn't delete anything).


Matt Metzgar said...

I would disagree with your statement that diets work. First, this study did not track any changes in lean mass. Though the subjects did lose fat, they most likely lost muscle mass as well (which will of course slow their metabolism).

Second, all the groups except Ornish (which lost the smallest amount anyways) showed fat regain from 6 months to 12 months.

A person can lose weight with a diet, but that weight will come back over the period of a year or two. I'm unaware of any multi-year studies that show anyone losing more than a pound or two on any type of diet.

Brad Pilon said...

Hi Matt,

You raise some good points.

The study did actually track fat mass, however they reported it in a way in which we can't decipher actual pounds of fat lost (change in percent of bodyfat).

Most likely if the subjects were weight training then the lean mass loss would have been minimal for all diets.

I think you and I are on the same thought wave..just wording our thoughts differently.

By saying "diets work" what I mean is that caloric restriction does result in weight loss, however you must pick a version of "diet" that you can maintain within YOUR lifestyle.

Otherwise, you will slowly slip out of the diet and back into your regular eating patterns. As a result of this you're weight will also begin to slowly slip back to what it was with your regular eating patterns.

I agree that most studies only show a weight loss of 1-2 pounds per week, however this is 2 to 4 times better than the results of the best time, in the best group, for this particular study.

Thanks for writing in,


billy said...


I (thought I) posted a good long comment about this!

Oh well, I'll try again...

I was just saying that it was interesting that it seems that this diet failed to determine what it set out to: which diet is physiologically best for weight loss. What it DID show, however, is how REAL people interact with diets. How well they can follow them, how much they cheat, how easy they are to adhere to. How sustainable are they?

It would seem that none of these diets are really doing too well in that area (10 lbs in 12 months? Not too good...)

It brings up an issue I always think about: so many diets focus solely on what and how much to eat, how and how much to exercise; when really what people need is the psychological, emotional support and motivation to follow through and stick with it.

People debate over carbs, fats, etc., when really, most people know how to lose weight. They know what's healthy and what's not for the most part.

What they DON'T know is how to change the way they THINK about their relationships with food (and with the world) for the long term. There should be more "diet" books about just that!

Brad Pilon said...


I couldn't agree more with your post.

In fact, I feel like I should simply cut and paste it to my blog, and then just stop writing, because you have managed to encompass my main beliefs about dieting and nutrition - we need to stop stressing over all the little micro management issues, and get to the route of the problem.

Couldn't agree more.


1jonboy said...

Great blog with great information I hope you can visit my website that has links to Weight Loss Programs
best regards John

Anonymous said...

Hey, while searching for widgets for my blog, I stumbled upon and wow! I found what I wanted. A cool news widget. My blog is now showing latest news with title, description and images. Took just few minutes to add. Awesome!

Kim said...

its a very useful blog with much information

Experience diet diary said...

I'm from Japan.
Glad to meet you.

Indeed I am sorry,Please link to this site.
Keep it up please.

Anonymous said...

Hi guys, amen to the comments about getting a handle on why we overeat. i have read an excellent book by Di Harris called "stop dieting and lose weight". she advocates everything in moderation. eat when you are physically (not emotionally) hungry and learn to recognize when you are just comfortably full and most importantly ENJOY your food.