Zoe Harcombe writes on one of the latest “observational/epidemiological” diet studies to come out recently. It relates to my post earlier today and, frankly, it is too good not to add on. Tom Naughton has a great article discussing recent studies as well. Both are spot on and if you have an interest in the science, you won’t want to miss them.
Laura Dolson has a primer on the basics of interpreting dietary studies. You may recall we discussed this here and here. Observational/epidemiological studies are terrible at determining causation with diet. They easily confuse people. They are less expensive and that is the only advantage. They were used in the past to successfully answer questions about infectious diseases in the early part of the 20th century. They were used to successfully determine that smoking caused lung cancer. But since then, try as they might, epidemiologists have tried to apply their methods to diet and health without success. At all. But they need the work and the medical journals need publications, so you will continue to see them. Mainstream media loves to report and sensationalize them. Randomized Controlled Trials are much, much better at determining causation in diet. Regarding weight loss alone, there are at least 17 rct studies that show a low carb diet is superior. There are NO rct studies which conclude a low fat diet is better. The problem with Rct studies are their cost. But they give us much more valuable information.
The other day we looked at a graph depicting the latest information released by the World Health Organization and the Food and Agriculture Organization of the United Nations on saturated fat intake and heart disease. This information is not new. David Evans at Healthy Diets and Science has an unbelievable collection of studies supporting this. There are over 50 studies going back decades on heart disease alone. The more saturated fat you take in, the less your risk for heart disease. Think about the BAD dietary advice you have been given that has been based on BAD science over the last 30 years. Now take the time to review the hard scientific evidence of the effects of diet & lifestyle on health from over 1,000 studies from research centers, universities and peer reviewed scientific journals. Think about what you could do with YOUR LIFE starting today given the right information!
There is evidence that increasing saturated fat in your diet will ease allergy suffering. This makes sense because a high carb diet is pro-inflammatory. Insulin is an inflammatory hormone. Allergies occur when your immune system perceives things like pollen, pet dander, food, etc as a foreign substance. Your immune system then uses IgE antibodies to create an immune response against these substances. So increase saturated fat in your diet, decrease the carbs and decrease the inflammation!
We have to put away our fear of normal saturated dietary fat. People struggle with this concept. Saturated dietary fat is not only safe but protective! For people in our generation this is an idea that is hard to accept. But it is no longer debatable! Dr. Eenfeldt discusses this in a recent post. The study was just published in March 2012. I think the chart is self explanatory. More saturated fat, less heart disease. Less saturated fat, more heart disease.
In 1988, the U.S. Surgeon General decided to finally put the controversy to rest. They decided to gather all the available evidence together to show that saturated fat causes heart disease. Eleven years later the project was disbanded. The reason given was that “the amount of expertise and human resources needed to complete the project was not fully anticipated.” Right. It took them eleven years to figure this out? What had they been doing up until then? We know that the science behind the theory was clearly not holding up. If they had found the smallest bit of evidence you can bet that not only would they have publicized it, but we would have never heard the end of it.
Still worried about normal saturated fat? Look at Japan. Japan at one point led the world in stroke mortality. In the mid-1980′s, there was a campaign to increase normal dietary fat to reduce stroke deaths in Japan. Boy did it ever fall! It is the single greatest fall in death rate for a disease in any given population that many of us have ever seen! A study published in 2004 showed that the risk of dying from a stroke in Japan fell from 1334 (per 100,000 people) to 224. Almost a 6 fold reduction! If you are wondering whether the people in Japan started dropping over from heart attacks after increasing their dietary fat, that did not happen either!
Finally, look at the Women’s Health Initiative. This was a randomized, controlled study that included 50,000 women. It ran 8 years. Half the women were given a low-fat diet which ended up being about 29% of the diet. The control group ate 37% of the diet as fat. For the women who had a prior history of cardiovascular disease, if they ate the low-fat diet there was a 26% greater chance of having a heart attack. The authors failed to comment on this. When they were asked to comment, no reply was given.
This is just a small sampling of the evidence disproving the dietary fat concerns. There is much, much more. Saturated fat is not harmful and is Helpful!
We are in the throes of a childhood obesity epidemic. I don’t think this surprises anyone. Likewise, I don’t think it surprises anyone that childhood obesity puts these kids at risk for more serious health problems down the road. However, when it comes to identifying which children are overweight and which kids are at risk, as parents and physicians we tend to misperceive. We incorrectly categorize who is overweight and who is not. The medical literature is filled with studies to support this. We tend to worry that our kids are underweight when it should be the other way around. BMI and the rate of BMI change, are the best objective tools for measuring this. Electronic medical records make it easier to track BMI from year to year in the office. At home you can calculate your child’s BMI using any of the many online applications. We worry the most about kids over the 95th percentile for BMI, but kids above the 85th need to be watched closely. The good news is that if we have a child in this situation, we know what to do. We implement a diet that lowers carbohydrates and increases normal dietary protein and dietary fat. The child gets healthy nutrition and he/she finds the more normal growth curve.
Here is a study posted on David Evans’ website showing the childhood obesity trend in relationship to the decrease in normal dietary fat consumption and the significant increase in carbohydrate consumption from the 1960′s into the 1990′s. Yes, I know this is another observational study and correlation does NOT mean causation. But if you are considering the LCHF diet and need a study to get you started, this will help. My advice is to just try your own study (We call that “N=1″, which means your study will have 1 participant — you!).
In the picture above, you are looking at glucose in the bloodstream. The picture was taken with a scanning electron microscope. We don’t know if the glucose came from sugar cane, refined wheat or refined corn.
In a way, it’s fun to watch large agribusiness fight it out in the courts and in advertising. Here is a nice post from dietdoctor.com. The large sugar companies don’t even deny that sugar is the issue anymore. Now they are trying to blame others — like in this ad where Big Soda targets Big Food. Do people even believe this ad? Probably, otherwise they would not bother spending the money to put it up and there are smart people running these companies. By the way, I thought the diagram at the bottom comparing rates of soda consumption with Type II Diabetes was a nice touch. Here is an article that illustrates how the High Fructoses Corn Syrup Industry and the Sugar Industry are pitted against each other.
The point is this: IN YOUR BODY IT DOES NOT MATTER WHERE THE GLUCOSE COMES FROM (I’m not yelling, I’m just emphasizing). It can come from sugar, refined wheat, or refined corn. The body handles it all the same way — you get an elevation of your blood sugar level, your pancreas produces a large amount of insulin, and that blood glucose has to be stored SOMEWHERE in your body. It may go into fat cells, it may stick to coronary arteries, or it may may stick to the neurons in your brain (resulting in Alzheimers). Your body does not care where the glucose comes from. So that means YOU have to start worrying about where it comes from. We use the concept glycemic load to discuss how much glucose a person is taking in — whether during a meal, in a day, or in a year. That is a concept that I want you to become familiar with. It is extremely important. As these businesses vie for market share, they don’t care one bit about your health. They will spin it however they can spin it. As long as you remember that your body does not discern between sugar, HFCS or refined wheat, you will be in good shape.
“Doesn’t meat cause cancer?” I hear this comment often enough from people. I don’t blame anyone for thinking this. This line of reasoning has been drilled into us along with a host of other healthcare/dietary myths for years. But the real question is why? YOU NEED TO UNDERSTAND WHERE THIS INFORMATION CAME FROM IN ORDER TO MAKE HEALTHY EATING DECISIONS. The idea that meat causes disease comes from a very large observational study called the Harvard Nurses Study. Here is the most recent “Meat causes cancer” study published in JAMA just this past April.
Remember, though, we learned about observational studies the other day. Observational studies look back in time to try to pick up patterns. They are terrible at determining causation. In fact, the Nurses Study uses what is called a “food frequency questionaire.” This is a questionaire handed out to all the participants in the study — in this case over 100,000 nurses since 1976. They are asked to recall what they ate in the last few months and approximately how much. This should raise a red flag immediately. How many of us remember what we had for lunch last Tuesday? Right. Me neither (although I know it was healthy!). There are some very smart people who would like to eliminate the use of the “food frequency questionaire” in dietary studies. It is a cheap way to gather data and that is about the only advantage. The information is not very accurate.
The Nurses Study looked at other behaviors as well. Things such as smoking, alcohol intake, exercise patterns, etc. Finally, the study looked at health problems. It kept track of cancer, heart disease, mortality, etc. All very important things when you are trying to tell people how to eat. When you are looking at an observational study like this, particularly when it takes place over the course of 20-30 years, you have to account for “compliance bias.” There are people (believe it or not) that listen to what health professionals tell them. They exercise, abstain from smoking/alcohol, get the right amount of sleep, etc. You can imagine that in the early 1980′s, when the USDA adopted its disastrous food pyramid, that health conscious people immediately cut back on meat and increased their carbohydrate consumption. Gary Taubes does a wonderful job explaining compliance bias in this blog post.
“So what Dr. Hoop. Cut to the chase.” OK. When the people at Harvard gathered the data from the Nurses Study, they determined that “eating meat” will increase your disease risk by 0.2 fold. “Dr. Hoop, that does not seem like a very big number.” You are right. To put this in perspective, smoking would increase your risk by 20-fold. Most good scientists will not accept a risk adjustment less then 3 or 4. “OK, Dr. Hoop. But I’ll take a 0.2 reduced risk for disease by abstaining from eating red meat.” Hold on! Remember all those confounding variables! In fact, the people who ate red meat, were also the people who smoked, drank, did not exercise and probably did other things that were not healthy. There is a blog post from Dr. Andreas Eenfeldt in Sweden that captures this in the study that was published in April of 2012. It is worth scrolling down and looking at all the confounding variables.
This is what I would LOVE TO KNOW, but probably never will know. How much longer those people in the “Less Meat” column would have lived had they actually eaten LCHF. In other words, had they NOT listened to the prevailing low-fat theory, they would have lowered their disease risk FAR GREATER then 0.2. They did everything else to maintain their health. I believe that the people who ate more meat (as determined by the “Food Frequency Questionaire”), had a 0.2 greater risk for disease because of their other health habits (smoking, lack of exercise, alcohol, etc.). Eating meat was probably the only healthy thing they were doing. And, if you remember the compliance bias, the only reason they were eating meat is because they were ignoring what was “supposed” to be healthy at the time.
To those of us who advocate and promote the LCHF diet, to see the Nurses Study used to perpetuate the fear of eating meat is beyond frustrating. Robb Wolf recently posted his disgruntlement on his blog. It is an observational study only. Yet so many people have been convinced that meat is dangerous because of this study. It is a belief, for many people, that probably will not change very soon. Do not let this study fool you!
Here is one of my favorite videos on the obesity epidemic. Dr David Diamond Ph.D. talks about how the “light bulb” came on for him. He realized he had been given bad information and after he started eating REAL food (LCHF), his body began to heal.