"Clean" vs. "unclean" eating studies?

To the OP. Have you looked into the Glycemic Index?

I found these yesterday but wasn't sure they were really relevant. But since you mentioned canning (I think I understand your question better now) I thought I'd bring it into the discussion.

The Glycemic Index was a theory in the 1980's and seems to have taken hold in the 20-30 years that followed with TONS of additional studies done in the years that followed.

The Glycemic Index is a way to understand how different foods (and cooking processes) impact digestion and ultimately blood sugar in humans. This impacts insulin production which can create energy and/or excess fat in the human body. While this index is most important for people who are sensitive to sugar (diabetic/hypoglycemic etc) it is interesting to see how cooked foods and "whole" or raw foods differ in their impact (or have little change at all) in the way they impact a person's blood sugar. Anyway I thought it was interesting stuff and thought I'd share.

1981's study (very small obviously but the additional reports build on this research)
http://ajcn.nutrition.org/content/34/3/362.abstract?ijkey=84bea5d97e32ea70ecda10544873437c01fe8a9a&keytype2=tf_ipsecsha

1995 report that attempts to gather all the existing data from Glycemic index testing into one report. I found it helpful to understand what exactly they were measuring and why (less cryptic than the 1980's study)
http://ajcn.nutrition.org/content/62/4/871S.abstract?ijkey=c1484c6014467ac51be36f20926487088e65cd50&keytype2=tf_ipsecsha


1986 large study of men and supports whole grain over processed grain in dietary consumption
http://care.diabetesjournals.org/content/20/4/545.abstract?ijkey=ebfc5e1368e6964511c68ae3ac90be366560c9a8&keytype2=tf_ipsecsha

1986 large study of women - results indicating that consuming high glycemic foods and lowering fiber content in food may cause diabetes
http://jama.jamanetwork.com/article.aspx?articleid=414104

10 year study finished in 2000 - links high glycemic food intake to increased risk of heart disease
http://ajcn.nutrition.org/content/71/6/1455.abstract?ijkey=f4516015221008ee73e985a1bbd184c6b39f310d&keytype2=tf_ipsecsha

Small scale study of teens - Subjects consumed identical test meals at breakfast and lunch that had a low, medium, or high GI. The high- and medium-GI meals were designed to have similar macronutrient composition, fiber content, and palatability, and all meals for each subject had equal energy content. After breakfast, plasma and serum concentrations of metabolic fuels and hormones were measured. Ad libitum food intake was determined in the 5-hour period after lunch.
The rapid absorption of glucose after consumption of high-GI meals induces a sequence of hormonal and metabolic changes that promote excessive food intake in obese subjects. (my note: WHY do we not have more studies like this??)
http://pediatrics.aappublications.org/content/103/3/e26.full

Another study that looks to link refined carbohydrates/high GI food with insulin growth that leads to colon cancer:
http://annonc.oxfordjournals.org/content/12/2/173.abstract?ijkey=b86e153a1b64423e464128164ea6dd6ce4181ace&keytype2=tf_ipsecsha

This one is a bit cryptic to me. Maybe you'll understand it better? Appears to be a study looking to link a protein receptor in a patient's DNA to diabetes based on how they respond to High GI foods? (My best guess.. lol)
http://ajcn.nutrition.org/content/73/3/574.abstract?ijkey=8f99cb21a65856b0931c683a829c94207bb7dc8a&keytype2=tf_ipsecsha

I found the conclusions in this report pretty interesting so I'll paste the part I found useful below the link:
http://archinte.jamanetwork.com/article.aspx?articleid=647390

"The glycemic index of foods reflects their tendency to affect postprandial glucose and insulin concentrations.7 Thus, given equal amounts of carbohydrate, food with a high glycemic index leads to higher postprandial glucose and insulin concentrations than food with a low glycemic index. Although it has been long known that foods affect glucose and insulin concentrations differently, the clinical significance of the glycemic index remains controversial.8 Current dietary guidelines in the United States do not recommend the use of glycemic index, although many recommendations are generally consistent with the consumption of foods with a low glycemic index and avoidance of refined foods with a high glycemic index.9,10 Examples of foods with a lower glycemic index include various legumes, pasta, and minimally refined products.11 Examples of foods with a higher glycemic index include potatoes, white breads with refined flour, and refined grain cereals. Recently, several studies found that the glycemic index is positively associated with the incidence of type 2 diabetes mellitus12,13 and cardiovascular disease.14"

There are 120 total references listed in this report. I'm still reading through the ones I feel I can understand but the data supporting the Glycemic Index as a way of determining foods that are positive or negative for the body does seem very solid:
http://ajcn.nutrition.org/content/76/1/5.full.#ref-6


I wanted a "GI for dummies" since I knew I wasn't understanding 100% of the stuff I was reading above. So I went to good old Wikipedia to see if what I was understanding from the complex stuff above could be clarified in normal English. Its also a jumping off point to find the opposing viewpoints too if those interest you. There's also tons of additional references here.
http://en.wikipedia.org/wiki/Glycemic_index

And heres a report from the American Diabetes Assn. that discusses the impact of cooking vs non cooked food on the GI:
http://clinical.diabetesjournals.org/content/29/4/155.full

"Physical form: Generally, the more processed a food, the higher its GI. For example, instant oatmeal has a GI of 79, whereas steel cut rolled oats has a GI of 55.

Food combinations: When carbohydrate foods are eaten as part of a meal, the GI of the meal changes based on the average of all the GI values factored together. Thus, a useful message for patients is to complement a high-GI food (such as rice) with low-GI foods (such red beans or legumes).

Cooking time: Longer cooking times may increase the glycemic impact of a food by breaking down the starch or carbohydrate and allowing it to pass through the body more quickly when consumed. Pasta cooked al dente (for 5–10 minutes) has a slightly lower GI than pasta cooked longer.

Acidity: The more acidic a food is (e.g., pickled food or those containing vinegar or lemon juice), the lower the GI. For example, sourdough bread, which uses a lactobacillus or lactic acid culture as part of the leavening process, has a lower GI than white bread.

Physical entrapment: The fibrous coat around beans, seeds, and plant cell walls in whole grains acts as a physical barrier, slowing access of digestive enzymes to break down the carbohydrate. Thus, many whole grains and legumes have a lower GI."

So from what I'm understanding from what I've read so far: Some foods impact your body more than others in their natural form. Light processing of foods (boiling, baking, canning etc) has a very small or no raise on the GI. Processes that dramatically change the chemical makeup of food (such as the enrichment and bleaching process of white flours, rice and extruding process of cereals) dramatically changes how they process in your body. These become high GI foods have been shown to indirectly cause heart disease and some types of cancer, and pretty much proven to cause diabetes.

This seems to mesh with other reports I've read where Mediterranean and low carb diets lower the risk of these diseases (presumably because they eliminate those super processed grains and focus on other foods that are low GI)

Obviously this doesn't answer all your questions, but hopefully gives you another avenue to research.

Happy reading!

Whatever the deal is, my own experience is this; I ate fast food all my life and survived right up to and after my heart attacks.

Now that i'm eating clean, I feel healthier and better about myself. Does anything else matter really?

NO!

Ok, just putting this one out there as there seem to be some people on this thread that are pretty good at research and analyzing studies and scientific texts. This is from the book "The Science of Skinny" written by a biochemist as to why on a molecular and cellular level certain foods are bad for health and weight loss. (full disclosure, this book is pro clean eating) To a novice like me the book is filled with what appears to be actual science, including diagrams of molecules, etc.

"...raw sugarcane is brimming with enzymes and nutrients. By contrast, refined sugar is devoid of these nutrients and the built-in enzyme systems that exist in raw sugarcane (and other naturally sweet foods, such as fruit). So when you eat a cookie made with refined sugar, your body freaks out. It knows that to properly digest the sugar, it needs these missing nutrients and the corresponding enzymes. Therefore, your body is forced to adapt by pulling stored nutrients (especially calcium) from your bones, tissues, and teeth, just to digest the sugar in the cookie you just ate. This is called leaching."

Unfortunately she does not cite a source for this info, which is why I am bringing it up. I have read and heard that certain vitamins etc don't work as well as when you get them through food. Since nutritional science is still so new, they don't really know conclusively why this is. It may be that the vitamin works most effectively in combination with something else that is present in the whole food. (ie the way calcium and vitamin d work together) This could be a potential argument for how some types of processing can have negative health consequences.

She also goes on to explain how sugar contributes to an acidic environment in the body (which prefers slight alkalinity) and how cancer cells require acidity to grow. I believe there is some accepted science behind that as well.

Please be nice, I genuinely would like to know if there is any validity to this!

Leaching happens to some degree when other nutrients are devoid in many many applications not just refined sugar but the key to good health is to have a diverse diet that helps maintain as many nutrients as possible to minimize leaching for all those possibilities. It's a good argument though when someone is trying to promote a bias against one nutrient from the hundreds available. I would imagine if someone consumed mostly table sugar they would be in trouble.

There are a lot of variations on the definition of clean. I did a lot of research trying to figure it out. I came up with a lot of people touting Paleo as clean, but then I came across "whole 30". It's Paleo but a lot more restricted if you can imagine. I don't think these programs are made for long term "dietary" lifestyle changes, but I have done them a few times in an effort to cleanse. (by cleanse I mean break the junk food cycle. I am a sugar addict) Each time I have done this, I feel better, I learn more about myself and I usually kick one bad food habit.
It has been almost 4 years since I put sugar in my coffee. Last year I gave up soda, now I drink my coffee black. All of these are baby steps, that add up.
For me I learned that when I have something sweet, I crave more of something sweet. I need to save it for when I am prepared to fight it for the next few days, or not have any at all.
I can't think of any study, that wouldn't be skewed one way or another toward one group.

You know, another thing I keep running into in these studies is the Alternate Healthy Eating Index. Over multiple studies, across tens of thousands of subjects, this index seems to be a predictor of chronic disease. Only...I can't seem to find the actual index itself, only references to it in the studies.

The AHEI index study has some method issues (limited self-reported caloric analysis, etc...) but it concludes you should eat vegetables, fruit and fiber.

http://ajcn.nutrition.org/content/76/6/1261.abstract?ijkey=5fc1cbe4f392b69f908541efb4b5507fd84024d4&keytype2=tf_ipsecsha

It has nothing about "clean" eating. Variety with a reasonable amount of fresh produce. This can be met in any clean or unclean diet practice.

I just came in to compliment OP, and many others in here, because for 8 pages, this has stayed relatively on topic, there seems to be a decent amount of friendly debate going on with some minds open to considering alternate view points, and most have tried to stay focused on science and less on anecdotal evidence. So far, this is one of the most neutral discussions I have ever seen on this much lauded topic - from both sides.

I hope I did not just jinx this thread.

Thanks! We've been very fortunate that some genuinely curious people without an agenda have posted. And there has been a wealth of good information...unfortunately, very little of it actually addresses the original question regarding "clean" eating studies. I think they don't exist.

I think they don't exist for the reasons that have been pointed out throughout this thread. In order to conduct a true scientific study, there needs to be test groups and control groups and the parameters guiding each of those groups need to be clear and consistent. From these 8 pages of relatively logical debate, we still have yet to find a consistent definition of "clean" and "unclean" and therefore, it will be impossible to truly measure the impacts of either style of eating in a scientific experiment.