You Ask, I Answer: Breakfast

In Gwyneth Paltrow's new site she gives nutrition advice.

She recently said that a person should try to go 12 hours between finishing dinner and beginning breakfast.

She states that breakfast should be a "break from the fast" (12+ hours) to allow the system to rest and detoxify.

What do you think of this concept?

-- Sarah (last name unknown)
Via the blog

Gwyneth didn't have much nutritional credibility with me earlier this year when she blogged about the health miracles of detoxing. Let's find out if she has redeemed herself with her latest batch of advice.

No need for a drumroll -- the answer is NO, she has not redeemed herself.

The number of hours that pass between your last bite of food prior to hitting the sack and waking up the next morning are irrelevant.

There is nothing magical about twelve hours. Eating breakfast nine hours after finishing dinner has no negative effects on health or digestion.

Let's assume you had a late snack at 11:30 PM and went to bed an hour later, at 12:30 AM. Eight hours later (at 8:30 AM) you wake up. I find it absolutely ridiculous to expect you to wait three hours to eat breakfast!

If anything, by the time you have your first morsel of food, you'll be so famished you'll overeat.

I would much rather you focus on what you're eating for breakfast. Waiting twelve hours to load up on a breakfast low in fiber and nutrients but high in added sugars and calories makes no sense.

My other concern with this "health halo" surrounding fasting and spending hours without eating is that it is a half step away from glorifying anorexia nervosa.

Where did celebrities get the idea that an Oscar and a health credential are the same thing?

You Ask, I Answer: Depression & Vitamin D

I just got my blood labs done to test for vitamin D deficiency.

My doctor said that my recent depression symptoms and joint pain could be resulting from that.

I knew about rickets and vitamin D deficiency in children, but what is this chronic pain/fatigue/depression stuff in adults?

How does vitamin D deficiency play a role in that?

-- Christine (last name unknown)
Via the blog

Thanks to more funding -- which means more research -- we are finally getting a glimpse at all of Vitamin D's important functions.

Many people don't realize that the term "vitamin" isn't even 100 years old (that anniversary will occur in 2012).

Vitamin D, meanwhile, wasn't discovered until 1922.

In any case, recent research on vitamin D status, depression, and joint pain appears promising (more studies are needed before any of this can be established as fact, though).

As far as depression is concerned, this is the reasoning:

* Blood samples of individuals experiencing clinical depression show lower levels of
25-hydroxyvitamin D (the active form of vitamin D measured in blood).

* The brain contains vitamin D receptors, which vitamin D uses in the synthesis of vital peptides and compounds.

* Recent studies on individuals suffering from Seasonal Affective Disorder (SAD) concluded that those who supplemented 600 International Units of vitamin D reported feeling better more quickly than those who did not supplement. It is worth noting that neither group used special UV lamps for the study.

This is not to say that vitamin D "cures" depression. The current line of thinking is that low vitamin D status can exacerbate some types of depression, and that correcting this inadequacy may be one factor than can help speed up recovery.

As for the second half of your question -- since Vitamin D is tightly linked with calcium and phosphorus in bone metabolism, it only makes sense that inadequate levels could have an effect on joints.

The latest studies theorize that deficiencies of vitamin D make it more difficult for the body to repair cartilage and joint damage from arthritis.

I completely side with scientists and researchers who recommend daily supplementation of 2,000 International Units of vitamin D for the following groups of people:

* Dark-skinned individuals
* Adults over the age of 65
* Anyone living north of Atlanta (from October to April)
* Anyone with limited sun exposure

You Ask, I Answer: Exercise

Is exercise enough?

I know plenty of long distance runners that subsist on ice cream and candy bars, even well into their middle-age, and have perfect health.

Can exercise overcome poor dietary choices? If so, to what degree?

-- Corey Clark
(Location withheld)

Exercise in itself is NOT enough.

Sure, exercise can help with cardiovascular heath, respiratory health, and musculoskeletal maintenance, but you also need proper nutrition to keep all systems running properly.

Exercise does not provide Omega-3 fatty acids, fiber, monounsaturated fats, or phytonutrients.

How do you know these long-distance runners who subsist on junk are in perfect health? Have you seen their blood labs?

Just because someone is thin and has a six pack does not necessarily mean they are in perfect health. They could have high blood pressure, low bone density, and low intakes of most vitamins and minerals.

You Ask, I Answer:BHT/BHA

I bought some gum today and the last items on the ingredient list are "BHT and BHA to preserve freshness."

Do you have any idea what that is? It sounds freaky and "chemical"-y.

-- Lori Echter
[Location withheld]

Chewing gum ingredient lists -- especially those of sugarfree gums -- are always fascinating. Artificial sweeteners and dyes abound! But, hey, at least they whiten your teeth, right?

Since BHT and BHA are antioxidants (they prevent the oxidation of oils and fats), their presence increases the shelf life of gum and many other packaged foods.

Yes, gum contains oils (in the form of glycerol, which impart a waxy texture).

You are correct when you say that these two ingredients sound "chemical"-y. They ARE chemicals. BHT stands for butylated hydroxytoluene, while BHA is an acronym for butylated hydroxyanisole.

Although the United States considers them safe to include in food processing, the European Union has banned BHA from all cosmetic products. BHT, meanwhile, is banned from the British food supply amidst reports of its carcinogenic risks and harmful renal effects.

A significant problem here is not so much that the miniscule amounts of BHA or BHT in food are deadly, but rather that because so many people eat heavily processed diets, the amounts of BHA and BHT being consumed worry some researchers.

For what it's worth, the Food & Drug Administration claims to be conducting "further research" on BHT (they have been saying this for at least a decade).

Whenever possible, I suggest you purchase products that use natural antioxidants to preserve freshness (i.e. tocopherols, also known as vitamin E).

You Ask, I Answer: Coconuts/Coconut Oil

I have a question about coconut oil and lauric acid.

[A] co-worker was doing some research online, and found out that coconut oil is supposedly antimicrobial.

The main fatty acid is lauric acid, which supposedly helps boost metabolism by activating the thyroid.

Is there any truth to those statements?

-- Brandon
(via the blog)

Coconut is a controversial fruit. Although almost entirely made up of saturated fats, there are plenty of books and websites dedicated to its "miraculous" weight-loss and healing properties.

However, two red flags immediately go up.

Number one? Most websites that hail coconut oil as a holy food that cures you of all ills while simultaneously helping you look years younger inevitably -- and predictably -- end up hawking some sort of coconut product.

Number two? My "BS" radar always beeps loudly when one food is referred to as a "miracle" or "cure-all".

The links between coconut oil and thyroid function have never been even remotely established in any studies. I believe that "fact" stems from an article in health and diet supermarket trash tabloid Woman's World, which is as reputable as a Vegas used car salesman.

Although lauric acid is one of the "least unhealthy" saturated fats, it certainly doesn't justify including massive amounts of coconut oil in your diet.

Before I continue, let me share one of my biggest nutritional pet-peeves. I always find myself counting to ten and taking deep breaths when I hear someone say something along the lines of, "but there are tribes in Polynesia that LIVE on coconuts and their heart disease rates are really low!"

The problem with that statement is that those Polynesian tribes also have extremely different lifestyles, dietary patterns, and environmental factors affecting their health.

Extracting only the coconut eating and adapting it to a traditional United States diet does not guarantee YOUR risk of heart disease is suddenly going to match that of a random member of that Polynesian tribe.

With that out of the way, let's continue.

My verdict on coconut oil? For the time being, treat it like you would all other saturated fats. Don't shun it, but do keep it to a certain limit (if eating 2,000 calories, aim to consume no more than 20 grams of saturated fat a day).

Also, I would much rather you consume coconut meat (or shredded unsweetened coconut) rather than coconut oil, as the actual fruit provides more nutrients.

If antimicrobial properties of food are your thing, coconut oil is not the only source. Garlic, green tea, cumin, and cayenne pepper also have antimicrobial components.

You Ask, I Answer: Supplements

Do you object to supplementation in general via a basic multivitamin/mineral product?

I recall [reading in the Center for Science in the Public Interest's] Nutrition Action Healthletter that adult males [should] avoid iron supplementation (perhaps due to a possible link between excessive iron intake and the development of a certain type of cancer?).

Is iron something that adult males should indeed avoid in a supplement?

[Lastly,] do you see any merit to taking curcumin or cumin supplements (especially for someone with an inflammatory disease such as asthma)?

Obviously, a whole food is preferable, but I think that massive amounts of curry would need to be ingested in order to derive any possible benefits.

-- Rob White
Boston, MA

My stance on supplementation varies depending on context.

I despise the notion that as long as you take a multivitamin once a day, you don't need to worry about the nutrient composition of what you eat the rest of the day.

Multivitamins do not offer the vast amount -- literally THOUSANDS -- of healthy phytonutrients and other compounds naturally found in foods.

Additionally, absorption from multivitamins is often lower -- and less effective -- than if that same nutrient is derived from actual foods that contain those nutrients.

I do, however, fully support the supplementation of Vitamin D. Unless you live near the Equator, your body can not synthesize this nutrient from sunlight between the months of October and April.

For the record, I recommend supplementing 2,000 International Units of Vitamin D a day.

I also don't have a problem with individuals supplementing a specific vitamin or mineral that they would otherwise be deficient in (i.e.: vegans without access to fortified foods and B12).

The issue of iron supplementation and men can also apply to post-menopausal women. Since iron is very hard for the body to excrete (menstruation being the exception), supplementation in these two populations raises the risk of a condition known as iron overload.

Iron overload can cause a variety of symptoms and problems, from heart arrhythmia and hypothyroidism to impotence and arthritis.

This is why, if you examine the label on a "men's formula" multivitamin, you will find that iron is MIA.

As far as curcumin supplements in regards to asthma, it gets complicated. There is very little data on the efficacy of these supplements. Consequently, dosage values have not been clearly determined.

Additionally, certain individuals (those with weakened immune systems, diabetes, and stomach ulcers) are advised to steer clear of these supplements, as they can aggravate those conditions.

I think you are better off implenting more curry-spiced dishes into your diet. After all, populations that are believed to benefit from this spice include it in their recipes, not swallow it in pill form.

You Ask, I Answer: Skinny Bitch

What do you think of the book Skinny Bitch?

-- Jamie Pierce
Salt Lake City, UT

Skinny Bitch advertises itself as "a no-nonsense tough-love guide for savvy girls who want to stop eating crap and start looking fabulous!"

While I do give the book credit for rightfully criticizing the treatment of farm animals and dedicating a Marion Nestle-inspired chapter to the politics behind the approval process of artificial sweeteners and other substances, I summarize it as "an often inaccurate, wannabe-"shocking" nutrition book that sometimes spouts crap and is under the impression that insulting the reader is fabulous!"

Skinny Bitch claims to "finally tell you the truth about what you're feeding yourself."

However, despite its "hip" title and grrrrl-power writing style that launched it to the top of the New York Times bestseller list, it is riddled with faulty facts, hyperbolic pronouncements, and silly suggestions.

One of the authors is a former agent for Ford Models. First red flag.

Why do people who have never studied nutrition science consider themselves authorities? Would you trust a dentist who never studied dentistry? Would you trust a surgeon who never set foot in medical school? I certainly wouldn't. So why take nutrition advice from someone who hasn't dedicated time to studying it -- especially someone who works in an industry obsessed with unhealthy body shapes?

Author number two is a former model who holds a Masters degree in Holistic Nutrition from Clayton College of Natural Health. Not surprisingly, the quality and reputation of this institution are highly questioned.

There's two red flags before you even open the book.

In any case, Skinny Bitch makes the argument that the only way to be healthy is by becoming a vegan who shuns alcohol, white flour, and caffeine.

The authors repeat this over and over and particularly enjoy cursing at the reader for ever thinking they could be healthy by including any sort of meat or dairy product in their diet.

Even more disturbingly, they prey on readers' body image fears by making the case that not only does any amount of meat and dairy make you sick, it also makes you -- gasp! -- fat.

Allow me to share some passages that resulted in an "ugh!" and an eyeroll from me.

* "Soda's high level of phosphorus can increase calcium loss from the body, as can its sodium and caffeine."

While phosphoric acid in soda has indeed been linked with leached calcium from bones, it is only an issue for individuals who are not getting sufficient amounts of calcium in their diets.

Have these two ever bothered to look at the nutrition facts on a can of soda, though? Soda is very low in sodium.

A can of Coca Cola, for example, contains 35 milligrams (that's 1.4% of the suggested daily maximum intake). Ironically, the frozen vegan burger products the authors endorse contain as much as 500 milligrams of sodium per serving!

As for the caffeine-calcium link -- that's also weak, at best.

* The authors make several references to drinking 8 glasses of water a day. As I have explained in the past, this recommendation stems from a huge misunderstanding by the mainstream media.

* "One study even links caffeine to an increased susceptibility to diabetes."

Bad science alert!

Had the authors bothered to thoroughly research the literature on caffeine and diabetes, they would have discovered that caffeine consumption is linked to a lower risk of diabetes among healthy individuals. The studies they refer to are ones suggesting that people who already have diabetes may benefit from cutting back on caffeine in order to improve their blood sugar levels.

* "Acidic foods cause your body to produce fat cells..."

They apparently believe in one of the biggest -- and off-base -- nutrition myths. Lentils, blueberries, and chickpeas, for example, are categorized as "acidic foods." They now make you fat? Wow, and to think silly uninformed me considered them healthy all this time!

* "When we eat fruit with other foods... it rots and ferments in our stomach."

Not surprisingly, that ludicrous statement is not attributed to any source. Right, because it's science fiction!

* "We have food rotting, decomposing, and fermenting in our intestinal tracts and colons, hence the need for colonics."

Did the author with the Masters degree ever take a human physiology course? Clearly not! Otherwise, she would know that nothing can cling to the colon and "rot away" since the cells that line that organ slough off several times a day.

* "You don't see many tigers getting colonics, do you?"

No. Fortunately for them, rip-off artists don't exist in their species.

* "Your body can't handle animal fat, so it settles like lumpy shit all over your ass, thighs, sides, arms and stomach."

I'll let that ridiculous quote speak for itself. Is this what holistic nutritonists are being taught? Sigh...

* "If you want to get skinny, you've got to be a vegetarian."

Before I comment, let me remind you that I am a pescatarian who follows a strictly vegetarian diet 90% of the time. I am by no means a meat enthusiast, nor do I have stock in the beef industry.

That said, the idea that vegetarian = skinny is ludicrous. After all, vegetarians can eat ice cream, cakes, cookies, muffins, pizza, french fries. They can consume more calories than they need and, consequently, gain weight.

Once again, I can't help but wonder: THIS is the nonsense that passes for a #1 New York Times bestseller these days?

* "Dairy products produce mucus."

Another myth these authors clearly didn't research.

* "[Dairy products] are the perfect thing to eat if you want to be sick and have a diseased body."

As much as I dislike the narrow-minded notions that dairy products are the only way to get calcium and absolutely necessary for human health, I am also irritated by the frantic and inaccurate warnings that dairy products are equivalent to chugging Draino.

* "Consuming high amounts of dairy blocks iron absorption, contributing to iron deficiency."

Ugh. The same can be said about phytates in whole grains. In fact, the extremists folks at the Weston A. Price Organization make that very argument -- which, like this one, has very little relevance.

There is severely faulty logic at work here. Yes, calcium inhibits iron absorption, but this applies to all sources of calcium (i.e.: broccoli, bok choy, mustard greens, and tempeh) -- not just dairy.

* "Eggs are high in saturated fat."

Absolutely untrue. One egg contains approximately 1.5 grams of saturated fat -- that's 0.4 fewer grams than a tablespoon of olive oil!

* "You will pee in your pants when you see how much weight you lose from giving up dairy."

If you give up any food and don't replace the calories with something else, you will obviously lose weight. If, however, you replace the 91 calories in a cup of skim milk with 91 calories from soymilk, don't count on any changes.

* "Do you really believe milk can be made fat-free? Get your had out of your ass. Milk = fat. Butter = fat. Cheese = fat. People who think these products can be low fat or fat free = fucking morons."

The f-word! How "edgy"!

First of all, there is no such thing as low-fat or fat-free butter, so that particular example makes no sense.

Additionally, skim milk is not a mythical food item that only exists in supermarkets operated by unicorns and mermaids. So, yes, milk CAN be made fat-free.

* After pages upon pages of criticizing processed foods and sugar, the authors go on to recommend a variety of frozen vegetarian burgers, soy ice creams, and tofu hot dogs. HUH? Frozen vegetarian foods, like other frozen items, are high in sodium. Vegan hamburgers are processed food. Soy ice creams, like dairy-based ones, contain added sugars.

* From the FYI chapter: "Donate blood. You can save a life and lose weight at the same time."

I think that was when my eyebrows hit the ceiling.

Alas, I could go on (trust me, I could!), but I think you get the point.

To "make up" for their verbal abuse at the reader, the authors conclude the book with positive-thinking mantras lifted right out of The Secret ("every day in every way my stomach is getting flatter") and a clearly-tacked-on-by-a-public-relations-friendly-editor reminder that, despite the title of the book, unrealistically thin illustrations on the front and back cover, and constant references to weight, "they couldn't care less about being skinny."

You Ask, I Answer: Gummy Bear Food Label

Here's a mystery for you.

I am looking at a bag of Haribo gummy bears. According to the food label, there are 3 grams of protein per serving.

How can that be? I thought candy was just sugar?

-- Marilyn (last name withheld)
New York, NY

I sought out a bag of these gummy bears and immediately looked at the ingredient list: "corn syrup, sugar, gelatin, dextrose, citric acid, starch, artificial and natural flavors, fractionated coconut oil, carnauba wax, beeswax coating, artificial colors: Yellow 5, Red 10, Blue 1."

The answer to your question comes courtesy of the third ingredient -- gelatin.

Remember, gelatin is made from the jelly-like protein substance that remains after dissolving animal tendons, ligaments, skin, and bones in boiling water. Consequently, gelatin is approximately 85% protein.

All gelatin is animal-derived. "Vegetarian candies", meanwhile, use plant-based thickeners.

You Ask, I Answer: Grapes vs. Wine

Out of curiosity, how many grapes would someone have to eat to equal a serving (how many ounces is that?) of wine?

Also, is grape juice just as healthy as wine?

-- Patricia (last name unknown)
Berkeley, CA

Is it only red grapes that offer health benefits?

-- "WifeMomChocoholic"
Via the blog

As I mentioned in a previous post, the same buzz-worthy components in red wine are available in red grapes. One slight exception to the rule is resveratrol, which is simply more concentrated in wine.

One reason you don't hear quite as much about white wine, by the way, is because the production process separates the grape's flesh from the skin (for red wine, the whole fruit is used).

If you want to talk numbers, your average bottle of wine is made from approximately 600 grapes.

Now, let's do some math.

A standard wine bottle contains roughly 25 ounces. According to MyPyramid guidelines, one serving of wine is equal to 5 ounces.

Therefore, one serving of wine contains 120 grapes. That helps us better understand the recommendations of drinking, rather than eating, the fruit.

That is not to say, of course, that you need to eat 120 grapes to get health benefits (FYI -- one serving of fresh grapes is made up of 15 individual pieces).

As far as grape juice is concerned -- the health benefits are not quite up to those of wine.

Remember, the vast majority of grape juices are made from concentrate (which is largely made up of the naturally-occurring sugars). Consequently, a lot of the polyphenols and antioxidants found in grape skins do not make it to the final product.

Although red wine (and, therefore, red grapes) offers a wider variety of healthful components in larger amounts, don't cast off white grapes. Even though white wine is not made from grape skins, the fruit's flesh offers a fair share of polyphenols and antioxidants.

You Ask, I Answer: Iron & Athletes

I know women who menstruate need more iron than men and postmenopausal women.

What about male athletes?

I have seen some literature that suggests they need more iron [than men who are not athletes], but my coach said he has never heard of that.

-- Scott Julin
(Location unknown)

Athletes of all sexes and ages require higher iron intakes than the average population.

The term "athlete", by the way, refers to people who train for significant amounts of time at high intensity.

I am often surprised at the amount of people who jog for 20 minutes three days a week and think they suddenly have the nutrition requirements of an Olympic medalist!

The reason for this higher requirement (roughly equal to that of vegans and vegetarians)? Athletes -- especially long-distance runners -- experience microscopic intestinal bleeding as a result of their intense physical activity.

You Ask, I Answer: Popular Healthy Foods

Why is it that there is much talk about eating olive oil, wine, and tomato products and not simply olives, grapes, and tomatoes?

Surely the benefits of the processed forms are even more present in the whole form of the food.

Or is that not the case?

-- Corey Clark
(Location withheld)

I love this "thinking cap turned on" question!

Here is my take on each of the pairings:

Olive oil vs. olives: Everyone cooks with some sort of fat; not everyone eats olives.

So, in order to have as many people as possible reap the benefits of olives, it makes more sense to suggest they use olive oil in their cooking/salad dressings rather than eat olives.

Also, olives have a much stronger taste than olive oil. Many people who enjoy the flavor of olive oil do not find olives palatable.

Although olives offer more vitamins and minerals than olive oil, 120 calories of olives (equal to 1 tablespoon of olive oil) offers almost half of the daily recommended limit of sodium!

Tomato products vs. whole tomatoes: Cooked tomatoes offer higher levels of lycopene than their raw counterparts.

Wine vs. grapes: This is one I never understood. Grapes offer the same healthy compounds as wine. This is why I always tell people that if they regularly eat grapes but do not drink wine, they are not missing out on any health benefits!

I personally think this comes back to the "reaching as many people as possible" goal that applies to olive oil.

You Ask, I Answer: Folate vs. Folic Acid

What is the difference between folate and folic acid?

Are they two different minerals?

-- (Name withheld)
Bridgeport, CT

Actually, they are the same vitamin!

Folate is a B vitamin (known in a small handful of scientific circles as "Vitamin B9") found primarily in beans, legumes, green vegetables, fruits, and, if organ meats are your "thing", beef liver.

Folic acid, meanwhile, is the the synthetic version of folate (i.e.: the type available in supplements).

In what I consider an odd turn of events, our bodies absorb folic acid more efficiently than folate.

You Ask, I Answer: Red Mango

When you blogged about Red Mango frozen yogurt, you endorsed it as a healthy treat.

I also saw that in your recent ConAgra children's frozen meal post, you commented negatively on the 18 grams of sugar it contained.

A small, original (plain) Red Mango yogurt also has 18 grams of sugar.

So now I'm slightly confused -- is Red Mango good or bad? How can 18 grams be good in one thing, bad in another?

-- Lexi (last name withheld)
New York, NY

One of my biggest grips about food labels is that they do not differentiate between naturally-occurring sugars and added sugars.

Naturally-occurring sugars are found in fruits and vegetables (in the form of fructose) as well as dairy (as lactose).

Added sugars (mostly in the form of sucrose) are added on to foods during processing.

Although naturally-occurring and added sugars offer the same number of calories (4 per gram), naturally-occurring sugars are different in the sense they "come with the package."

When you bite into an apple, you are getting sugars along with vitamins, minerals, and a wide variety of health-promoting phytonutrients (some of which we have yet to discover!).

If you eat the same amount of sugar naturally found in an apple in the form of table sugar, you are getting empty calories (they are void of vitamins, minerals, and phytonutrients.)

In the case of Red Mango, the 18 grams of sugar refer to naturally-occurring AND added sugars. Approximately 10 to 12 of those grams are naturally-occurring, so you're only getting 6 to 8 grams (1.5 to 2 teaspoons) of added sugar.

By the way, I have a slight problem with Red Mango referring to their original flavor as "plain", since plain flavors of regular (non-frozen) yogurt do not have any added sugar.

In any case, this is very different from that frozen meal I posted about, which got its 18 grams of sugar from the chewy candies it offered as dessert.

You Ask, I Answer: Egg Yolks (Part 2)

How unhealthy are egg yolks?

Is it true that some people have more of a chance (due to genes) of producing more LDL cholesterol and [that] only these individuals should eat egg yolks in moderation?

-- Lori (last name unknown)
Via the blog

Egg yolks are branded with an undeserving "unhealthy" label that has proven hard to shake off.

It was formerly believed that high intakes of dietary cholesterol resulted in high blood cholesterol levels. We now know, however, that blood cholesterol levels are linked to intakes of of trans fats and most saturated fats.

It is true that some individuals have a genetic predisposition for high cholesterol. Consequently, they are recommended to limit their intake of whole eggs to three per week.

If, however, you do not fall into that category, you can safely eat one egg a day.

As far as I'm concerned, the average healthy individual should concern themselves much more with saturated fat than cholesterol.

After all, very low intakes of cholesterol simply mean your liver makes up for it by creating more.

As I pointed out during Season 4 of Bravo's reality competition show Top Chef, people often make significant nutrition mistakes when avoiding meats high in cholesterol. These meats are usually much LOWER in saturated fat and, therefore, a healthier option than varieties low in cholesterol but high in saturated fat!

Your average large egg provides 77 calories and only 1.5 grams of saturated fat. It also doesn't hurt that it's a good way to add riboflavin, B12, selenium, and biotin to your diet!

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.

You Ask, I Answer: Chunk Light Tuna

I generally eat about 4 cans of chunk light tuna a week. Reasoning: Omega-3's are good and mercury is low in chunk light tuna.

However, I just read an article saying that mercury was high even in canned tuna, although previous sources have said that mercury levels in canned tuna are low enough to be safe.

The same sources state that only the larger predatory fish such as shark and albacore tuna need be avoided.

What's your take?

-- Corey Clark
[Location unknown]

Chunk light tuna contains approximately one third of the mercury found in the same amount of albacore ("white") tuna.

According to current recommendations, adults can safely eat up to three cans of chunk light tuna a week (the suggestion for albacore tuna caps off weekly consumption at one can for adults).

Don't get too comfortable, though. You still need to glance at the ingredient list since some varieties of canned light tuna contain yellowfin tuna, which contains higher amounts of mercury.

You Ask, I Answer: Eating at Night

Why did you say [in your Michelle Obama post] that the principle of not eating late [at night] is hogwash?

Doesn't the digestive system interfere with sleep if it is still working full-time at bedtime?

-- Elsa (last name unknown)
Via the blog

The recommendation of not going to bed with a full stomach makes sense if you are talking about acid reflux or heartburn.

Finishing up a large dinner and falling asleep on the couch half an hour later can be problematic since acidic gastric compounds from the stomach can enter the esophagus and cause symptoms that disrupt sleep.

I was referring, though, to the common myth that not eating after a certain hour (usually 7 PM) leads to weight loss, as if there were a "magical" caloric bewitching hour.

Eating after 7 PM will only result in weight gain if whatever you consume puts you over your caloric needs. A piece of fruit or a cup of low-fat yogurt are no more fattening at 10 PM than they are at 2 PM.

What gets left out of these inane "weight loss rules" is that, very simply, the more hours you are awake, the more calories you are likely to consume. Hitting the sack an hour and a half after dinner doesn't leave as much room for hunger as staying up for another four hours.

You Ask, I Answer: Protein On The Go

Got an idea for a source of protein for my daughter that I can take with me out and about during the day that doesn't require refrigeration?

-- "n/a"
Via the blog

Nuts are always great; peanuts, almonds, cashews, walnuts, and pistachios are easily transportable sources of protein.

Although all nuts should be stored in the refrigerator (to slow down rancidity of fats), it is certainly okay to carry some with you throughout the day.

I am not a big fan of protein bars. The vast majority of them are loaded with added sugar and saturated fats.

You Ask, I Answer: Wild Blueberries

Are wild blueberries more nutritious than regular blueberries?

-- Sophia Durbitry
[Location withheld]

The main differences between wild blueberries and "regular" (planted) blueberries are their size (wild blueberries are smaller) and taste (wild blueberries are tangier and a little sweeter).

From a nutritional standpoint, there isn't a huge difference.

Wild blueberries are reported to have higher levels of antioxidants, but I wonder if that is simply because they are smaller in size (a half cup of wild blueberries contains almost twice as much individual berries as half a cup of cultivated blueberries).

Even if, ounce by ounce, the wild variety is higher in antioxidants, cultivated blueberries already contain a wide array.

Incorporating blueberries -- wild or otherwise -- into your diet is a great move. As the popular idiom suggests, "don't sweat the small stuff."

You Ask, I Answer: Cabbage, Radishes, Calcium

My family eats a ton of red cabbage.

Is this a fairly healthy, cruciferous vegetable and a good source of calcium?

What about radishes?

-- Dennise O'Grady
Bay Head, NJ

Like all other cruciferous vegetables, red cabbage offers a wonderful array of unique phytonutrients and flavonoids that have been shown to help reduce the risk of a variety of cancers, particularly colorectal and bladder).

It is not, however, a good source of calcium. Unlike some of its calcium-powerful relatives (bok choy, broccoli, kale, mustard greens, and turnip greens), its absorption rate is quite low.

Whereas slightly less than one cup of kale steamed kale provides the same amount of calcium as a half cup of milk, you need three cups of steamed cabbage to reach that same amount.

Slight aside: For maximum absorption of all nutrients and components, opt for steamed, rather than raw, cabbage.

Radishes do not particularly stand out from a nutrient composition standpoint. Although they offer almost every single vitamin and mineral, each one occurs in small amount.

Alas, nutrition isn't solely about vitamins and minerals. The antioxidants that give radishes their natural hue are very beneficial to health.

As with cabbage, radishes are not your best source of calcium. Due to their low absorptive qualities, it takes four and a half cups to match the amount of absorbable calcium in a half cup of milk.