You Ask, I Answer: Food Pyramid

Do corn and potatoes fall into the "grains" or "vegetable" category in the food pyramid?

-- Tom O'Farrell
Boston, MA

As far as the United States Department of Agriculture is concerned, potatoes and corn are members of the vegetable group.

Remember, the food pyramid categorizes foods by nutrient profile.

Although corn and potatoes are higher in carbohydrates than other vegetables, their vitamin, mineral, and phytonutrient content is more similar to that of vegetables than grains (we are talking about corn-on-the-cob and baked potatoes here, not Fritos and Pringles!)

I understand the USDA's decision from a simplicity standpoint, but it is not completely accurate in the case of corn, which is both a vegetable AND a grain, depending on how it is harvested.

Although most people associate corn with processed junk (where it either shows up as high fructose corn syrup or corn oil in ingredient lists), it offers a good amount of nutrition when eaten fresh (off the cob) or simply popped and sprinkled with a little salt, parmesan cheese, or nutritional yeast for flavoring.

For what it's worth, a large ear of corn contributes 127 calories -- along with vitamin C, phosphorus, manganese, potassium, and most of the B vitamins -- to your day.

No Wonder Potatoes Have A Bad Reputation

Arby's is offering a new side item on their menu -- loaded potato bites (pictured at left).

Uh oh, the term "loaded" is generally code for "artery and waist busting."

This is no exception.

These "yummy pieces of fluffy potato, deep fried and loaded with cheddar cheese and bits of bacon" are accompanied with a ranch sour cream dipping sauce.

A large side order (10 pieces) adds 707 calories, 14 grams of saturated fat (almost three quarters of a day's worth), and 1,600 milligrams of sodium (two thirds of a day's worth) to your tray.

The ranch dip, meanwhile, contributes an additional 158 calories, 4 grams of saturated fat, and 277 milligrams of sodium.

This is calorically equal to two orders of large fries at McDonald's.

You Ask, I Answer: Potatoes/Walter Willett's Healthy Eating Pyramid

I don't really know anything about the science of nutrition, so I won't state an opinion either way on the potato issue. But have you read Willett's book, Eat, Drink, and Be Healthy?

I think the pyramid is misleading by placing potatoes up there without an asterisk or something, but he does go into detail in Eat, Drink and Be Healthy about studies showing that potatoes cause a spike in blood sugar in the same way that refined grains do.

Again, not a scientist so I can't evaluate the merit of the studies and whatnot, but I'd suggest you check it out so you can decide if you agree.

Personally, I like potatoes a lot...but I mostly like them in less healthy ways (not crazy about the skin, like them mashed, etc), so I try to limit them.

Working at Harvard School of Public Health as I do, it's easy to feel a bit oppressed by the pervasiveness of Willett and the Healthy Eating Pyramid, though!

-- Daphne (last name unknown)
Via the blog

Your question brings up several issues worth mentioning (by the way, I realize you are not in favor of the "potatoes are just as bad as sugar" argument, so this is not a "response" to you).

I agree with Dr. Willett on many nutrition standpoints, but the potato issue is one I see completely differently.

I have not read Eat, Drink, and Be Healthy, but am familiar with his reasoning for placing potatoes at the top of his Healthy Eating Pyramid along with white flour, sugar, and candy.

Willett bases that decision on potatoes' high glycemic index (basically, the degree to which they raise your blood sugar upon consumption).

The problem with that reasoning is that it only truly applies if a potato is eaten entirely by itself.

Have it as a side dish to a high-protein food (salmon, chicken, tempeh, etc.), top it with a little fat, and the glycemic index decreases.

Since a potato's skin is a good source of fiber, eating it helps lower the glycemic index.

As I have mentioned before, a potato is not a potato is not a potato.

Dehydrated potato flakes from a box that turn into instant mashed potatoes are very different from French fries, which are very different to a baked potato cooked in its skin, topped with olive oil, and eaten in conjuction with grilled salmon.

Besides, the glycemic index is not a very accurate way to determine what foods are healthy.

If you go by it, ice cream is a "better" snack than watermelon.

While it is helpful for people living with diabetes, I don't see it as the most useful tool for weight loss -- it leaves calories out of the equation!

If you were looking to cut calories, would you have half a cup of ice cream as a post-dinner snack or a cup of watermelon?

You Ask, I Answer: Potato Consumption

While a baked potato with the skin left on is a healthy choice, the question is: how do the majority of North Americans eat their potatoes?

-- Kate (last name unknown)
Via the blog

Great question.

Here is what the most recent figures from the United States Department of Agriculture reveal.

In 2002, the "average American" consumed 126 lbs. of potatoes.

Of these 126 lbs., approximately 24 came exclusively from potato chips (the average American consumed 6 lbs. of potato chips in 2002; it takes 4 pounds of potatoes to make 1 pound of potato chips).

Frozen potatoes (mainly french fries) totaled 61 pounds.

Some simple addition reveals that french fries and potato chips make up two thirds of total average potato consumption!

Not exactly the picture of health.

We are still missing some vital information, though.

Although baked potatoes offer a good deal of nutrition (Harvard's School of Public Health Chair Walter Willett's claim that potatoes and candy bars are basically nutritionally identical is ludicruous), this survey does not tell us how people are eating them.

Mainly, how many calories they are being topped with. A pad of butter? Three tablespoons?

What we certainly know is that such a high consumption of French fries doesn't spell out good news for our waistlines.

While a nutritious side dish consisting of medium baked potato topped with a tablespoon of olive oil (that's quite a bit!) adds up to 280 calories, a large order of fries at McDonald's contributes 570.

In The News: Revising the Food Pyramid

The folks over at the Harvard School of Public Health -- led by Walter Willett -- don't think the traditional USDA food pyramid (officially known as MyPyramid) doles out the best advice.

So, they proactively designed their own version -- The Healthy Eating Pyramid.

You can see a nicely drawn PDF version by clicking on the link above.

I prefer this version over the USDA's, but have a few critiques.

Although I like the inclusion of "daily exercise and weight control" at the base, I would prefer that section be titled "daily exercise and portion control."

Additionally, the "healthy fats/oils" category should place more of an emphasis on fats higher in Omega-3 (i.e: olive oil, walnuts, flaxseed) and less on ones offering very high Omega-6 levels (ie: soy and corn).

As I have discussed in the past, an improper Omega 6:Omega 3 ratio has its share of health implications.

Lastly, I strongly disagree with the inclusion of potatoes in the "eat sparingly" pyramid tip (accompanied by red meat, refined grains, sugary snacks, and salt).

It is one thing to eat potatoes in their nutritionally void skinless, deep fried version.

However, a baked potato, eaten with its skin, is a great source of fiber, potassium, vitamin C, folate, and magnesium.

Clearly, current obesity and diabetes rates can not be blamed on the ingestion of healthily prepared potatoes.

Your thoughts?