This headline could have been the tagline for my favorite book concerning dietary science and the history of dietary recommendations in the US, “The Big Fat Surprise”–

Nutritional Science Isn’t Very Scientific

In the online magazine Slate this morning they write that the potato, recently kicked off of the WIC program’s list of approved vegetables that may be purchased with WIC money, has been allowed back on the list. You can look at this news many ways, and Slate decided to look at the science behind both decisions. Guess what? The conclusion is that the science is murky, not pointing to a definite yes or no answer to the question “Is the potato good for you?”

You see, in the world of dietary advice there are lots of ways to answer that very question, but the best answer is another question:”Compared to what?”

If you are at the grocery buying food for your growing family and you can only afford either a ten pound bag of white potatoes or ten Lunchables to feed your babies for lunch, the answer to the question “Is the potato good for you?” is YES, put the lunchables back. Compared to ANY processed food, from anywhere, including Whole Foods or any health food store, the potato is far better food than anything in a box or bag. Processed foods are dead, and they are immune to rot. The fact that they will last almost forever in your refrigerator or in your pantry is not a feature, it is a bug. They are neither good for you, or for the microbes living within you. The potato, on the other hand is good for both. It is alive.

…a report released in February by the Institute of Medicine, an independent nonprofit, shows that white potatoes are an inexpensive source of potassium, fiber, and other needed nutrients, and one that people actually enjoy eating.

Potatoes contain everything that the potato needs, and when we eat them we get all of the nutritional value that an animal can get from eating a potato. This is far different than what you would get eating an exactly equal amount of starch calories from slices of industrial bread or crackers. These processed food examples might contain calories from carbohydrate just like the potato, but they are made from ingredients that have been completely disassembled in factories, then reassembled for the convenience of the grocer. The purpose of many of the ingredients is to make everything uniform and indestructible by time or spoilage. A very small amount of ‘vitamins’ will be added so that the product can bear a claim of ‘nutritious’…”Helps to build strong bodies 12 ways.” Eating a potato, a product of nature, helps to build strong bodies in countless ways.

The ‘science’ that advises us against eating saturated fats, red meats, salt, cholesterol, and the rest of the long list of things that are not ‘good’ for you, is not really very good science as far as science goes. Epidemiological studies that ask subjects to remember what they ate over the last year, then ask them what ails them, are obviously going to suffer from fragile human memory, and the desire of the subject to provide useful information. You can’t beat a study where every ounce of food given to the subject is cataloged and their outcomes are categorized and cataloged as well. Those studies are just now being conducted, and the results are in the future.

Most of our devout beliefs about nutrition have not been subjected to a robust, experimental, controlled clinical trial, the type of study that shows cause and effect, which may be why Americans are pummeled with contradictory and confounding nutritional advice. Nutritional bad guys that have fallen from grace in the national consciousness—white potatoes, eggs, nuts, iceberg lettuce—have been redeemed years later. Onetime good guys, like margarine and pasta, have been recast as villains. Cholesterol is back in the probably-won’t-kill-you column after being shunned for 40 years, as of the latest nutritional advice from the Dietary Guidelines Advisory Committee in February. (That advice was still too timid, according to Cleveland Clinic cardiologist Steve Nissen, who also wants the nutritional guidelines to admit our best evidence suggests fat isn’t bad for you either). And then there’s salt—don’t eat too little, says the newest research. You could die.

When I was a kid we started getting the advice that eating real butter was bad for you. My mom and dad cried foul and we never took that advice. Now, in my lifetime, I find out that all of you that fell for the advice to eat margarine were harming yourselves. The word is slowly getting out that butter and lard are actually healthy fats. The entire episode gives ‘science’ a black eye, but it shouldn’t. This is how science is supposed to work. It’s too bad they gave us advice before it could all really be studied, but actually, everyone eating carbohydrates instead of fats was one big long term study, and the results are in. Two thirds of Americans are fat and sick, and getting sicker. Those are the results of eating processed carbohydrates and added sugars to replace the fats we used to eat. The experiment should be over, but of course, it’s not. The sugar people are arguing that the science is still out over whether we should be adding their product to eight out of ten foods on store shelves. Let them argue. Eat your potatoes.