Christopher Gardner and the A to Z trial and beyond

I have followed the studies of Dr. Gardner for quite some time and one of the research studies he’s best known for is the A to Z trial.  His group showed some interesting results from the study and basically opened rifts in the nutrition world and how we as humans consume food. Dr. Gardner, known as a laid back, vegetarian Stanford nutritionist, was very open about his position as a vegetarian, and concluded that eating a diet high in carbohydrates, may not be the best approach to a healthy lifestyle.

Are you pulling your hair out and confused about which diet is right for you? Atkins, Ornish, LEARN, Mediterranean, Paleo, Zone?  It gets pretty confusing. Enter Dr. Christopher Gardner, he is a nutrition researcher from Stanford university. He is a pretty simple guy and exclaims that he was a philosophy major who only wanted to open a vegetarian restaurant before he came to Stanford. One of the more openly honest researchers out there, he is known for directing the A to Z trial. He has a video discussing the results of the study, and even though he thoroughly pissed off many authors of the many books written about the various types of diet, he openly stated, that if you look at the group as a whole, the Atkins group did the best. And mind you he said this at a time when the Atkins diet was being heavily scrutinized. Even though he is a devout vegetarian, he came to the conclusion that a low carb diet was better for health and subsequently changed his approach.  This is rare to see in the health sciences. In the research world, there’s so much motivation to perform the study and tweak it into how you want it to come out so you can get the next NIH grant.  In life, we are all individual and no one diet or anything for that matter is going to be the answer. The goal is to apply these types of studies to the real world.

What is the A to Z trial?

This was a 12 month-long trial comparing 4 weight loss diets. This study has 3000 days of reliable dietary history. This is huge, not many studies that have this amount of data. Participants were randomized to follow the Atkins, Zone, LEARN, or Ornish diets with close supervision.  All subjects were overweight / obese and women. The Atkins is a very low carbohydrate, the LEARN diet is the so called health professionals diet, the Zone diet is moderate carbohydrate, and the Ornish is a ultra low carbohydrate diet (scroll to the end of the article for exact macronutrient percentages).

What did they find?

At the end of the day, after random assignments of diet intervention, Atkins did the best in weight loss, decrease in triglycerides, increase in HDL, decrease in blood pressure, AS A GROUP. This is important because there was actually a lot of individual variability. Dr. Gardner, broke down the metrics for the people staying on the diet.  They showed that some people actually lost no NET weight during the entire year. The group that tried to follow Ornish, actually fell into a standard diet.  The ones who had the least weight loss had the highest insulin levels. And no one knew the insulin levels during the study, unless they checked it themselves from a company like direct labs.

Past the weight loss, they looked at the research closer.  They were able to identify people who were more insulin resistant than others and showed that there was a lot inter-individual variability. Meaning that there were some who lost a lot of weight, a little weight, or no weight despite adhering to a specific diet. In addition, when they further looked at the data, it was apparent that the people in the Ornish diet, had a really hard time adhering to this way of eating. In fact, it was found that most of these people actually followed more of a “LEARN-ish” diet. Likewise, it was also found that the people in the Atkins group had a hard time adhering to the diet and it was found that they followed more of the “Zone-ish” diet.

What’s the next study?

There are people who can improve their health on any type of diet. This has a lot do with your genes and epigenetics. As there is a lot of inter-individual insulin sensitivity, i.e. a lot of people have the ability to handle carbs and some do not!

Dr. Gardner’s group has a 600 person study evaluating this exact topic. This next study is ongoing and not finished, and is a continuation of the A to Z trial. They are studying only low carb and high carb diet interventions designed to be realistic and something that could be followed for life.  Each group is randomly assigned for 12 months to the one of the two groups.  Low carb group will consume 20 grams of carbs at first, then titrate up, the other group will consume 20 grams of fat, and then titrate up. Apparently, 95% of the participants were able to achieve this. The point is to eat the diet they could sustain for the rest of their lives. The goal is not to stay on the extreme diets for long periods of time as Dr. Gardner feels that staying so low either way will deprive many nutrients required for good health.

They are taught how to cut back added sugar, wheat flour or other flours. They will not eat processed foods, just farmers market real food. They will eat as many veggies as humanly possible, etc. It’s really important to understand the quality of what they are doing than just the numbers.

Realize, these are the people are beating themselves up, looking at the person next to them who is losing weight and doing fine, and just dumbfounded why they can’t lose the weight.  What Dr. Gardner is finding is that these people have some type of predisposition to not being able to lose the weight. There is something in their genes, environment, life, that will not allow them to achieve the metabolic state necessary for losing weight. Most of these people are insulin resistant. So he is also testing a plethora of inflammatory factors, and other markers. LDL particle size, microbiota, inflammatory markers are all important to measure and take in the whole picture.

There are a lot of people who are insulin resistant and do not have the ability to handle normal loads of carbohydrates at any given time. These are probably the same people who tend to not get enough movement, sunlight, have low vitamin D, and other metabolic derangements. At the same time, there are people who can lose weight and be healthy on any given diet (even the “gas station diet”). A lot of this has a lot to do with your genes and environment / epigenetics.


Plant pusher or animal pusher – no study overturns 50 years of research and block out the headlines.

Often when you read someone’s approach to how to consume food, it is laden with cherry picked data to support their way of telling you how to eat your food. One thing is for sure, no one research study is going to overturn 50 years of research in one sitting.  Even harder, is difficult to know which studies are heavily influenced by large lobbies or nutrition companies such as Nestle or Coca Cola.

A logical approach for many may be to start lower carbohydrate, and then over time reintroduce carbs slowly and monitor how you do. Use a glucose meter and see how long it takes the glucose to come back down to normal. As your metabolism changes by having better insulin sensitivity, you may be able to open your diet up to other foods and things that you might not have considered. At the end of the day you have to be practical about what you are trying to accomplish.

What is for sure, no one is in favor of processed flour or added sugar. How many vegetables can one possibly eat in a day?

So the real life lesson is that one can strive for perfect, but the result is probably going to be great.  People who were assigned to Atkins, in reality consumed more of a Zone diet.  So in reality, it shows that it is really hard to stick to a certain regimen of eating, and as in anything in life when you shoot for perfection, you get great.  Which is not a bad way to be.

In some of the athletes I train, this is exactly what happens.  I advise them to eat a certain number or carbs, protein and fat, and to cut out the refined carbohydrates. I know, most people will follow that advice 80% of the time. What usually happens is the athlete went to a birthday celebration and was out of their element, and well, you know the rest. The other common scenario is the types of food taken in during cycling or running varies a lot. Depending on their sensations, who they are training with, what environment they are in, that person is going go with more how they feel at the moment and consume whatever they feel necessary to make their training session go well.

The goal of the study and life is about optimizing metabolic flexibility or said another way, optimizing fat metabolism (OFM). At the end of the day, we all want to be able to burn fat, right?

Common ground principles – food should be good for you, good for the planet and taste good! And Don’t forget about the fact to eat and cook together!


Definitions of each type of diet intervention as described in the study:

Each group received specific target goals according to the emphasis of the assigned diet. The Atkins group aimed for 20 g/d or less of carbohydrate for “induction” (usually 2-3 months) and 50 g/d or less of carbohydrate for the subsequent “ongoing weight loss” phase. The Zone group’s primary emphasis was a 40%-30%-30% distribution of carbohydrate, protein, and fat, respectively. The LEARN group was instructed to follow a prudent diet that included 55% to 60% energy from carbohydrate and less than 10% energy from saturated fat, caloric restriction, increased exercise, and behavior modification strategies. The primary emphasis for the Ornish group was no more than 10% of energy from fat. Additional recommendations given for physical activity, nutritional supplements, and behavioral strategies were consistent with those presented in each diet book. The guidelines for the Zone and LEARN diets incorporated specific goals for energy restriction, while for the Atkins and Ornish diets, there were no specific energy restriction goals.