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Weight Loss Diets - The JAMA Study Revisited

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Recently, the Journal of the American Medical Association published a review comparing 4 diets, Atkins, Ornish, Learn and Zone, with Atkins coming out on top. Too bad that doesn’t mean Atkins is the best weight loss diet.

So which diet is better – Atkins, Ornish, Dash or the LEARN diet? Which one will help you lose the most weight?

Before you begin your weight loss low carb craze with renewed vigor, you should read the following.

When a study comes out saying a prominent weight loss diet is ‘better’ for weight loss than several other prominent weight loss diets, the difficulty is that many people will automatically assume the study’s conclusion to be fact.

There are serious flaws in the JAMA weight loss diet study. Our aim here is to help you understand why you should not take the JAMA study as necessarily the gospel (despite how many web sites are reporting it) and to give you some perspective on the strengths and weakness of Atkins, Lean, Zone and Ornish for weight loss.

In March when this study came out,  I considered running it here at LookCut and opted not to, primarily because I felt it was a very weak study.

Let’s review the JAMA study results.

The purpose was to compare popular weight loss diets and see which ones work the best.  311 overweight and pre-menopause women were randomly assigned one of the 4 diets – Atkins, Ornish, Learn and Zone.

At 12 months, average weight loss from Atkins was 10.3 pounds. Ornish weight loss at 12 months was 4.8 pounds. Learn diet produced 5.7 pounds of weight loss. Finally, the Zone diet produced 3.6 pounds of weight loss.

Atkins kicks ass and Zone blows, right?  Not so fast. Here are some things to consider.

A central criticism of this study is that there was very poor ‘compliance’ – in other words, ‘how do we know that the subjects ate what they were supposed to?’

We don’t. Compliance protocols in this study were poor. 

We don’t know exactly what the subjects ate. 

The authors of the study claim the reason compliance was nil was to measure the ‘real world’ impact of each diet.

The logic is a bit suspect.

If the purpose of the study was to compare different diet protocols, but we can't be sure the subjects actually followed the diet protocol, we have to be a bit careful in making conclusions about which weight loss diet is really best.

Let’s briefly look at each of the 4 diets and examine the strengths and weakness of each.

Basics of Atkins:
-Restrict to 20 grams (80 calories) of ‘net carbs’ per day

-Purposeful inducement of Ketosis (a state of extreme protein metabolization)

-Obtain ‘Critical Carb Level’ for losing weight ongoing
-Accurately identifies certain types of carbs as maladaptive for weight loss

-Will produce rapid initial weight loss due to hormonal shift from glucose deprivation

- Identifies problem of ‘bad carbs’ but fails to implicate processed foods.   You wind up eating a lot of processed proteins.

- Fails to identify role of natural carbs in weight loss.
- Idea of ‘critical carb level’ is fallacious. You can stay extremely lean on 70% carbs if they are not processed carbs.

Atkins is simultaneously responsible for popularizing many of the ideas that are spot-on for lifelong good nutrition, and also responsible for many of the current problems in dieting, such as the vilification of carbohydrate.  The problem is processed food.  That means, processed fats, processed proteins, and processed carbs – not just ‘good carbs’ and ‘bad carbs’.  The cumulative impact of processed foods on your body – fats, carbs and proteins – gives us the most comprehensive framework for understanding the problem in life long weight loss and weight maintenance. Atkins does a lot of things right, but is also almost singularly responsible for the ‘low carb’ movement that is really a misinterpretation of the problem of processed foods.

Basics of Ornish Diet
There are 2 versions of the Ornish Diet: The Reversal Diet and The Prevention Diet

Ornish Reversal
-Whole food vegetarian bias

-10% of calories from fat

-plant based fats o.k.

Ornish Prevention Diet

-Cholesterol prevention focus

-Reduce fat intake until total cholesterol is below 150

-Reduce intake of animal fats

-Whole foods centric

- Avoids processed fats

- Avoids processed carbs

- Fails to differentiate between high nutritional value of animal fat from naturally fed animals vs. animals fed processed grains.

- Needlessly construes against fats beneficial to cholesterol.

There is a lot to like about the Ornish Diet. For the most part, it keeps you away from processed foods. The central criticism of the diet is that it vilifies cholesterol as THE problem and in turn emphasizes avoidance of fat, particularly animal fat. This prohibition fails to acknowledge how different fats affect the body. Further, it fails to underscore the role of food processing in animals. Animal fats from grass fed animals profile substantially different from animal fats from grain fed and steroid fed animals.

There is now substantial research showing that the ratio of omega 3 to omega 6 fats from grass fed beef is markedly different from grain fed, making it one of the healthiest dietary choices in the world. The problem is not animal fats, but fats from animals fed processed grain. Simply put, some of the healthiest people in the world eat about 40% fats from grass fed animals. Give the diet points for its emphasis on lessening physiologic damage from certain foods, but it does not adequately address the full scope of the problem by failing to identify the beneficial role of different types of fats not just in mediating cholesterol, but controlling satiety and food intake.

The LEARN Diet

Basics of the Learn Diet
-The food pyramid diet
- Higher in carbs
-Low in fats

- Emphasizes vegetables and grains

- Emphasizes avoidance of bad fat

- Does not account for types of fat

- Emphasis on grains ignores allergies

- No accordance to food processing

Let me start with the fact that based on recent photos, the originator of this diet could be construed as being, ahem, what’s the word… voluminous? (sorry folks, pet peeve -  If you can’t lose weight yourself, you have no business telling other people how to do it) Okay - moving on to the objective part of this critique, the central criticism is its treatment of fats as bad, which simply does not take the research into account. You can lose weight on a diet higher in the right fats.  To be fair, there was a study about a year ago comparing this diet to The LEARN diet did better for weight loss.


The Zone Diet Basics
- Insulin control

- 40% protein, 30% carbs, 40% fats

- High dietary carbs make you fat

-Addresses the issue of hormones and diet
-Keeps you more glycemically neutral
-Acknowledges role of fats
-Does not differentiate adequately enough between processed and whole foods

-Over values hormonal response to carb, fat, protein ratios.

- Permanently sustaining protein intake of 40% presents health concerns – kidney’s, acidity, free-radical damage.

Along with Atkins, the Zone Diet has probably had more influence on our modern perceptions about diet than any other protocol. Like Atkins, the Zone Diet gets a lot of things right – the role of hormones and food intake, the role of fats, the problem of sugary carbs. The problem with the Zone is once you interpret its protocols through the paradigm of processed food being the problem; the rational for its 40/30/30 mandate disappears completely.  With high fiber, low glycemic load carbohydrate – whole natural food – you can eat 70% of your diet from carbs and still lose weight and feel great.

The JAMA study attempted to measure the weight loss impact of these 4 diets over a 12 month period. Unfortunately, as the authors of the study readily agree, there was no control over adherence to protocol, or what the subjects ate so we have be careful about jumping to conclusions.

One important thing to keep in mind is to differentiate between these diets as a way to eat for weight loss and a way to eat for life.

In a previous article we made the point that when it comes to weight loss, a lot of things will work – for a while. 

To lose weight, you could do a diet that was mostly carbs, or one that was mostly protein, or one that was very high in fats, and LOSE WEIGHT ON ALL OF THEM!

Why is this? The reason is simple. You may have got the impression in this article that I was speaking out of both sides of my mouth - one minute advocating high carbs, the next high fats, the next high protein. You are right!  Here is why.

The central weakness of the JAMA study is that each of the 4 diets advocates different ratios of protein, fats, and carbs as being THE key to weight loss.  The problem here is that what is left out of the discussion is the piece most central to sustained weight loss -VARIATION.  Alterations in your diet are as important as the diet itself.

ALTERATIONS in your diet alter your bodies hormonal and physiological response to food.  Hormones cause you to lose weight. Not diets. When your body adapts hormonally to what you are doing, your diet stops working.

I maintain between 6 to 8% body fat year round. One of the keys to this is simply that I vary my dietary composition a lot.

One day I will go high natural carbs, little fat, moderate protein, the next day I might go high fat, high protein, no carbs, the next day I might do high protein, little carbs and little fat. 


Ultimately, the main problem I see with the JAMA study is that it is postulating a bad question.  The question is ‘what is the best diet to lose weight’.  It leaves out important issues of long term satiety, fulfillment from food, stress, variation and the impact of processed food