Who Decides Serving Sizes?

How do they decide what a serving size is?
-- Gina

Believe it or not, we decide what a serving size is. The unit we see at the top of our nutrition labels (eight cookies, 100 grams, half a bottle, e.g.) comes from the average amount that Americans over the age of four consume in a single seating. And that average comes from federal food surveys. When nutrition labeling on packages became standardized in 1994, a U.S. Department of Agriculture task force used answers from the two previous Nationwide Health and Nutrition Examination Survey (known as the NHANES) to determine how much a typical person eats at one time. These averaged amounts are known within the industry as "reference amounts customarily consumed per eating occasion."
In other words, the current serving size on your bag of chips is a reflection of your fellow citizens' eating habits -- as they were between 1978 and 1988, when the two NHANES data were released.
But let's back up for a moment and discuss what a serving size actually is -- and is not. A serving size is a measurement that allows food manufacturers to create accurate and uniform nutrition labels across brands. It is not a prescriptive size that relates to health. "You’ve got servings related to the nutrition facts panel and then another issue is a reasonable portion of food to build a healthy eating pattern," says Dr. Robert Post, executive director of the USDA's Center for Nutrition Policy and Promotion. "That may be a little bit different. The serving size might be bigger than what we’d use in the nutrition world to promote good habits."

Instead, Post -- who previously worked for the task force that helped determine serving size -- recommends ignoring that measure when determining a reasonable portion size. "It's really an industry regulation tool," he tells HuffPost Healthy Living.
Serving sizes are also occasionally unrealistic. For example, a serving size of potato chips is ten chips. But when a family size bag is opened, we all know what happens -- half the bag disappears.
At this point you may be wondering what we starting wondering as we spoke to Post and investigated the industrial regulations on the U.S. Food and Drug Administration's website. What about foods that have been created since the labeling regulations were put in place? When a manufacturer wants to bring a new food to market, they must classify their food -- say, a "snacking cracker" (as opposed to a non-snacking cracker, a category that includes ice cream cones) -- and then look up the reference amount on a large database. The FDA and USDA share regulation, splitting jurisdiction by food group. The FDA, for example, is responsible for ensuring serving size accuracy for things like bread and yogurt; the USDA regulates things like meat, poultry and some egg products.
Of course, most of us do not have a new and innovative food to label -- we simply want to know how much snacking we can do to maintain a healthful diet. In that instance, you may be better off talking to a nutritionist or looking at the USDA's MyPlate guidelines. But it's always good to know where your health information comes from -- and it's a major advance for healthy eating that we have a tool through which we can equally measure different brands and versions of the same products.

Eat Before A Workout: Is It Necessary?

Honestly, when working out first thing in the morning, do I really need to eat before? Especially if I'm just doing a quick 30-minute run or elliptical?
-- Alicia, 26, Shreveport, Louisiana

With all of the marketing of sports drinks, bars, gels and powders, this is an excellent question to ask. There's certainly no harm in eating -- and it might help you meet your fitness goals by giving you more energy during the actual run or elliptical workout.
"It's a contradiction, but you really do need the calories to perform well," Barbara Lewin, R.D., L.D., a sports nutritionist who works with professional and Olympic athletes, said in an earlier interview about sports drink alternatives. "The calories are what's enabling you to work out at your best. If you're not well-fueled, you're not going to work out as hard."
And certainly, if you're planning an endurance training session, you must eat. According to Andrea Hacker Thompson, M.S., R.D., of the American College of Sports Medicine, endurance athletes should eat even when they aren't hungry. She wrote:

A race car never starts a race without new tires and a full tank of gas, so an endurance athlete should not start a workout without fueling. Eating before a workout guarantees that the body starts with a full tank of glycogen.

But even for those of us who aren't trying to run an ultramarathon, if we plan a rigorous session of 90 minutes or longer, getting a bit to eat beforehand is a good idea. To understand why, it's important to know how our bodies use energy during a workout. When we exert ourselves, we burn glycogen -- the cache of glucose we keep stored in our muscle and liver cells. After we've gone through that store of carbohydrates, we can start to feel fatigued. As Thompson explains for the ACSM, the body can store about 2,000 calories in glycogen. If you plan to go over that amount (and, wow, that's quite a workout if you do!), you could begin to get light-headed, weak or just plain exhausted.
But for a 30 minute treadmill session? You probably don't have to make a concerted effort to eat enough. You do, on the other hand, have to keep hydrated. Water is fine for a half-hour run, but any workout over an hour may require some electrolyte replacement -- such as a sports drink or a piece of fruit.
Beyond the question of whether or not to eat, there are other considerations. It's important not to eat too much -- or too little. And to know when to eat it. The Mayo Clinic provides a guideline, suggesting a small snack about an hour before exercising or a medium meal two hours before a gym session. For a full meal, they recommend giving yourself a three to four hour time period between eating and hitting the gym. Overdo it, and you could give yourself stomach cramps or even diarrhea.
Most of all, it's important to note your own reaction to food and figure out an eating plan that's right for you. Feel fine during a morning run, even without that yogurt? Skip it. But if you need a little something for extra energy, there's nothing wrong with starting with a snack.

Losing The Last 10 Pounds: Why Does Weight Loss Get Harder?

"Why is it so hard to lose the last 10 pounds? And why is it harder to lose weight the smaller I get?"
-- Tamara

Anyone who has tried to lose weight knows about those frustratingly immobile final five or 10 pounds. And while there are a lot of suggestions (just Google "last 10 pounds" and you'll enter an echo-chamber of weight loss advice, scientific half-truths and can-do enthusiasm), the truth is that several pretty straight-forward reasons can explain that unshakeable weight.
The first is easy to fix, but also the most psychologically daunting: it could be something called "diet fatigue," in which the repetitive behaviors dieting requires -- keeping a food journal, weighing portion sizes, skipping that glass of wine -- become arduous, hard to manage and, frankly, boring.
"Dieters become less careful, they are not taking the precautions they did in terms of knowing what they ate, how much," says Carla Wolper, Ed.D., R,D., research faculty at the Obesity Research Center at St. Luke’s and assistant professor in the Department of Psychiatry at Columbia Medical Center. "They may not realize they’re not as careful anymore."

That's not an invitation for blame -- it can happen insidiously and there's an easy solution. If the scale needle slows its descent, simply write what you eat down in a food journal. "Keeping food records is always recommended," says Wolper. "Studies show that people will lose weight, even if they don’t do anything different to their diet but simply start writing it down."
There is also the possibility that it's time to recalculate. When a person begins to lose weight, their metabolic rate drops. In other words, they need fewer calories to meet basic functioning and requirements. While a 150-pound woman might have a certain basic metabolic rate, that rate may drop when she becomes a 130-pound woman. That's why it's a good idea to reevaluate caloric needs after more than 10 pounds of weight loss, according to Wolper.
"People who are normal weight tend to eat fewer calories than people who are overweight, every day, forever," agrees Rebecca E. Lee, director of the Texas Obesity Research Center and a professor of nutrition in the Department of Health and Human Performance at the University of Houston. "It takes fewer calories to maintain a lower body weight. This doesn't necessarily mean that they eat less volume -- they might, but they also might eat more nutrient dense foods that have fewer calories, like vegetables, fruits, lean meats, etc."
There's an additional consideration regarding metabolism: something called "metabolic adaptation."
"When dieting, your body is forced to work on a reduced number of calories per day. Eventually your body adapts and trains itself to live on whatever calories it gets -- without losing weight. This built-in survival mechanism is your body’s way to protect you against starvation," says Dr. Caroline J. Cederquist, a metabolic expert and board-certified medical weight management specialists. "Once you have hit this point, you may manage to lose a few bonus pounds, but they will come off much more slowly and, before you know it, the weight you lost may start to come back on!"
So what can you do? Interestingly, the answer is not exercise. (Which is not to say you shouldn't exercise. Please exercise!) Very often we're told that building muscle mass will help rev up our metabolisms because muscle tissue burns more calories per hour than fat tissue does. But, as Wolper explains, the difference in caloric burn rate is minor. Fat tissue burns about two calories per pound per day, while muscle tissue of the same weight burns seven calories per day. If someone made a significant change -- transformed two pounds of fat into two pounds of muscle, that would amount to a difference of 10 more calories burned per day.
"The truth is that skeletal muscle doesn’t burn that much more than fat. Our brains burn the most calories. In fact, the lean tissue that burns a lot of calories is our heart, lungs, liver and brain. About 60 percent of the calories that are burned come from those four sources," says Wolper.
Exercise may help create a greater calorie deficit and that will help further along weight loss or help maintain sustained weight loss -- but it won't make a big metabolic difference.
Instead, in addition to redoubling food journal efforts and recalculating caloric intake for one's new size, Cederquist recommends something she calls a "metabolic adjustment phase." Instead of reducing calories, she suggests a two-week period of increased meal sizes. "During this phase, the goal is not to lose weight, but to readjust your body’s ability to metabolize an increasing number of calories, by increasing portion sizes and bumping up caloric intake."
Most of all, it's important to evaluate one's goals. Have you reached a healthy weight? If so and if continued weight loss is a huge struggle, it may be time to consider entering a maintenance phase. "Focus on the benefits of maintaining your weight loss," says Cederquist. "And remember that maintaining is as important as losing."

Cardio Or Weights First? Exercise Order Sometimes Matters

"Is there an order to working out? In other words, should I do weights first and then cardio?"
-- Karen 

Working out is always good for you. The good news is that, whether you do it before or after weight training, cardiovascular exercise like running, swimming, biking or machine-work will improve everything from your heart health to your mood to your chance of avoiding many cancers. And lifting weights helps with everything from bone density to metabolism.
But according to exercise physiologists and personal trainers we spoke with, the order of operation can change depending on a person's goal.
"This question is one of the biggest questions on people's minds when they go to the gym," says personal trainer and HuffPost blogger Jeff Halevy. For those who are seeking weight loss, cardio should come first, but if gaining muscle mass is the goal, it's time to hit the weight room first. But why?

Let's start with the muscle-building scenario. "Doing cardio first will induce fatigue that may compromise technique and possibly increase risk of injury," explains Fabio Comana, director of Continuing Education for the National Academy of Sports Medicine. Exhausting oneself with a big run right before weights and resistance training doesn't just up the risk of injury, it also means you'll have less energy to throw into a really good weight training session.
On the other hand, if you're looking to lose fat, Halevy recommends doing interval cardio training before getting started on weights. As he explains, the cardio will deplete your body's supply of glycogen -- the stored form of glucose in muscle cells and a primary material in our energy storage. Once glycogen is depleted, the body turns to more long-term storage sources, like fat.
"If your goal is strictly a lean body -- not to be strongest, or most powerful, but achieve maximal leanness -- I always recommend implementing high-intensity interval training at the beginning of each workout," says Halevy.
But that doesn't mean weights aren't important for fat loss. In fact, when it comes to analyzing the percentage weight loss that's comprised of fat versus lean tissue like muscle, weights have cardio beat overall.
"Resistance training should always be a consideration," explains Comana in an email. "Mother nature will help us lose lean tissue naturally (23 percent in women between ages 30 and 70), that we need to preserve. Diet and cardio also results in lean tissue losses (68 percent fat, 22 percent muscle / lean tissue). Whereas diet and resistance leads to 97 percent fat loss, and only 3 percent lean tissue loss."
There may be other reasons for doing cardio first. As Comana points out, many more people are familiar with cardiovascular exercise, so it will seem less intimidating and is thus more likely to happen. If the weight room is daunting enough to prevent a workout session, it's worth getting started on cardio and working your way up. And if another health goal -- say Type 2 diabetes or hypertension prevention or treatment -- is the priority, Comana recommends cardio over resistance. "Some diseases are better managed with cardio first, then introducing resistance training later," he told Healthy Living.
It's important to get the opinion of a doctor and certified personal trainer or exercise professional before proceeding, but the takeaway is simple: if you're exercising, no matter the order, you aren't doing anything wrong. Depending on your goal, you may want to choose one type of exercise over the other. Of course, you could alternate days and avoid the question entirely.

Should You Take A Multivitamin?

Is there a daily multivitamin that you would recommend to help boost energy for exercise?
-- Johnny, 23, East Bay, CA.

There are actually two parts to this question. The first is silent: should healthy adults be taking a daily multivitamin at all? If you believe the latest research, the answer is no.

The first thing to acknowledge is that, for the most part, Americans are not deficient in vitamins. A recent CDC survey found that we're sufficiently nourished in essential nutrients like vitamins A, D and folate. But just because we aren't deficient, doesn't necessarily mean that our vitamin levels are optimal. The question is, how important are optimal levels?

"You get your nutrients through your food. Through the milenia, that’s what the case was and we survived as a species -- in fact, we thrived," says Alice Lichtenstein, DSc, senior scientist and director of the Cardiovascular Nutrition Laboratory at the Jean Mayer U.S. Department of Agriculture (USDA) Human Nutrition Research Center on Aging at Tufts University and the author of a position paper on the usefulness of multivitamins. "To assume that we suddenly have lost this ability doesn't quite make sense."

While whole foods are a good source of nutrients, many public health researchers actually credit processed, packaged foods that have been fortified with vitamins for the nutrient-rich American diet. "Most people, if they are eating a generally healthy diet -- not a perfect diet, but a generally healthy diet, don't need a multivitamin," says Katherine Zeratsky, a registered dietician at the Mayo Clinic. "With things like breakfast cereals, nutrition bars, foritified grains and bread, because all those foods are fortified with other minerals, we are getting more than we realize and more than we need."

That doesn't make a multivitamin just redundant, it could make it dangerous: Lichtenstein points out to Healthy Living that a large surplus of supplemental folate may have an adverse effect on colon cancer and other research has found a relationship between folic acid supplements and prostate and breast cancers as well. Lichtenstein adds that an overabundance of vitamin A, to levels of toxicity, can manifest in accelerated bone loss.

Some vitamins are water-soluble and others are fat-soluble, explains Zeratsky. While water-soluble vitamins will pass right through the body and are expelled in urine (the inspiration for the popular "expensive urine" quip among physicians), fat-soluble vitamins are stored and build up over time, making it a bit easier to reach toxicity. Fat-soluble vitamins include D, E and A -- common inclusions in both fortified foods and in multivitamins.

What's more, a longitudinal study of women who took multivitamins and those who did not found that taking a regular multivitamin was actually associated with a shorter overall life expectancy. Critics of the study suggested that a bias may exist -- namely, that people who take a multivitamin may be doing so in response to overall health problems that reduce their life spans.

Although, according to Lichtenstein, the profile of the average multivitamin user is this: a middle-aged woman who eats healthfully and exercises and has an above-average education level. “The population who takes them is most often the population who is least likely to need them,” she says.

But there are people who can benefit from a multivitamin or certain supplements. One example that all of the experts we spoke with gave was women of child-bearing age -- and especially those trying to get pregnant -- who should ensure that they get enough folate to prevent birth defects like spina-bifida. Additionally, women who are going through or have gone through menopause might need a boost in certain nutrients, and those on specialized diets that are lacking in nutrition might also benefit. Because it’s so highly individualized, a supplement regime should be planned with a doctor.

Still, there remains no evidence that multivitamins are useful to overall or long-term health -- and some, albeit inconclusive evidence that they are harmful.

If you are going to take a multivitamin, Zeratsky says that she doesn't believe it will hurt. To ensure purity, she recommends looking for a brand that has been certified by a third party testing agency, like U.S. Pharmacopeal. Since vitamins and supplements are not regulated at the same level as food, it's important to know the source of what you're taking.

But long-term health isn't the primary concern at the center of this question. Johnny asked if there was a particular multivitamin associated with energy. Some people report, in a clinical setting (as opposed to a significant study) that the family of B vitamins gives them extra energy, reports Zaretsky. Though B vitamins are prevalent enough in our diet to maintain basic levels, it's possible that people who have an energy response to B vitamins may be low in these nutrients without being deficient. The extra boost may also increase energy, as the vitamins play a role in regulating metabolism.

Beyond that, when it comes to exercise, important vitamins for energy, muscle function, recovery and bone strength include vitamin D, vitamin C and electrolytes like potassium and sodium. Calcium is also really important -- not only for bone health, but for regulating how our muscles contract, according to Zaretsky.
That said, it's better to get these nutrients from sunlight (in the case of the hormone, vitamin D) and whole foods. "Our healthy diet goes so far beyond what a pill can offer -- known and unknown," says Zaretsky, pointing to the fiber and phytonutrients that foods contain and pills lack.

Agrees Lichtenstein: "The data generally supports better outcomes who are eating well-balanced diet. It's not particularly exciting, but from the perspective of what we can support in the research, that’s the best information we have."

What Is Metabolism: How Long After I Eat Is Weight Added To My Body?

"How long does it take for the food I ate to add weight to my body?" -- Bunter122 

Today's question comes from a reader who would prefer to stay anonymous, but it is certainly a thought that many people have had. Given that we all have different metabolic speeds, what is the average amount of time it takes food to be digested and then shunted off to its various purposes?
"We have a pretty good indication about the timeline from the sequence of ingestion, digestion, and egestion. The whole thing plays out over a span of roughly 12 hours on average," says Dr. David Katz, a HuffPost Healthy Living contributor and director of the Yale University Prevention Research Center. "By the time the residual waste of food is passing out of us, the useable parts have all been put to use -- for energy expenditure, as heat generation, or placed into storage, as either glycogen [from carbohydrate], or fat."
After you eat, the food passes through your stomach and small intestine in about six to eight hours, according to the Mayo Clinic. Then, it enters the large intestine where it is further digested. Putting it as delicately as possible, Mayo Clinic gastroenterologist Dr. Michael F. Picco writes: "Elimination of undigested food residue through the large intestine usually begins after a total of 24 hours. Complete elimination from the body may take several days."
For a complete understanding of what the body does to digest food, the National Institutes of Health has a great explainer. For our purposes, it is essential to understand that as food is digested, enzymes and hormones are secreted by the stomach and small intestines (as well as fat cells) and work to break down the carbohydrates, protein and fat we've eaten into usable material for our cells.

A growing number of endocrinologists -- those who study our hormone system -- are beginning to see the hormone response as far more complicated than previously thought, as well as far more individualized: there is a wider variance in how people respond to food, they suspect.
"While the question posed seems extraordinarily simple, I don't think that there can be a simple answer to it," says Dr. Kaveh Ashrafi, an associate professor of physiology at the University of California, San Francisco School of Medicine who studies fat metabolism. "The prevailing view essentially considers feeding behavior/exercise as the sole determinants of body weight. For this to be true, one has to assume that the body itself is simply an inert vessel; if you put more food in it, it must get fat, if you move it, it must lose weight."

Why Am I Hungry After A Big Meal?

"The day after a big meal, I go to bed feeling stuffed and wake up hungrier than ever. Why is that? Is my stomach actually expanding?"
-- Jessi, 30, New York 

"I must admit that I get this sensation," says Dr. W. Timothy Garvey, Chair of the Department of Nutrition Sciences at the University of Alabama at Birmingham and Chairman of the Obesity Scientific Committee for the American Association of Clinical Endocrinologists. Several Healthy Living staffers also related. So the good news is that you aren't alone.
But there's bad news too. You stumped our experts. "The truth is, we don't have a rigorous scientific answer for this," Dr. Garvey told Healthy Living, echoing a common sentiment among all the researchers with whom we spoke. There were several plausible theories.
But first, more good news: it's not your stomach expanding. "There’s no truth to that at all," says Dr. David Greenwald, Associate Director of the Division of Gastroenterology at Montefiore Medical Center in New York. "It's more likely that the stuff they ate didn't fill them up properly. People who eat a lot, but don't eat good things are likely to feel hungry again [soon]."

Big meals are often celebratory, which means they may include foods that are decadent rather than nutritious: starchy vegetables like mashed potatoes, white dinner rolls, cake. Foods that fall high on the glycemic index can make your blood sugar spike, causing a surge of insulin to drag it back down. The quick vacillation in blood sugar can cause a disruption to the normal cycle of leptin -- a hormone secreted by the fat cells that signals to the brain when you've had enough to eat. Foods that cause this type of response can encourage what is sometimes termed "fullness resistance."
In other words, that big pasta festival for your birthday? It'll just make you hungrier. But meals full of veggies, whole grains and lean protein may not create the same effect. Then again, "people who are eating vegetables, leafy salads are probably not overeating," adds Greenwald.
Still, Garvey wasn't convinced that leptin and insulin were the culprits here. It takes weeks for leptin production to respond to a dietary change because it's related to the size of fat cells, rather than the contents of a single meal. Instead, he suspected that ghrelin, a completely different hunger hormone that controls short-term regulation might be responsible.
"Leptin is a long-term regulatory hormone. It increases overall the amount of calories you take in. If your fat cells get bigger, they make more leptin and that suppresses appetite. If fat cells shrink, they make less leptin and that stimulates appetite," he explains.
"But ghrelin is a hormone that is secreted by the stomach. When you eat something, ghrelin is suppressed, making you not want to eat more. As time progresses after meal, after several hours, ghrelin rises," he says. "Some people have more rapid and pronounced rises in ghrelin in response to what they eat and that makes them want to eat more."
So what can a person do to avoid the dreaded after-binge binge? Of course, the most obvious advice is to avoid it in the first place: reasonable portions can be celebratory too. Choose foods that will keep you full longer: things that are high-volume and low-calorie, like leafy greens, and full of protein and fiber, like beans.
Beyond that, all you can do is some damage control: eat a sensible, filling breakfast (oatmeal! egg-veggie scrambles!) and know that the increased hunger will pass.