Harvard Study Finds Certain Foods – NOT Calories – Have a Strong Impact on Weight Gains and Losses

Individual foods are more important than calories when it comes to long term weight gains or losses, according to the study. Specifically, potatoes are associated with weight gain, along with sugar-sweetened beverages and meats, while foods like fruits, vegetables, whole grains, nuts and yogurt, are associated with weight loss, according to the study.

 “Modest changes in specific foods and beverages, physical activity, TV-watching, and sleep duration were strongly linked with long-term weight gain. Changes in diet, in particular, had the strongest associations with differences in weight gain… The idea that there are no ‘good’ or ‘bad’ foods is a myth that needs to be debunked,” said a researcher in a press release. The study appears in the June 23, 2011, issue of the New England Journal of Medicine.

When I was contacted by USA Today reporter, Oliver St. John, to comment on the Harvard Study, this gave me an opportunity to look over the study so that I could offer an analysis which would help not only “USA Today” readers, but me and my clients better understand it.

I found some of the claims made regarding the study incomplete.

While this is an interesting study and confirms much of what we know about healthy and unhealthy foods, I’m concerned about the sweeping conclusions for the following reasons:

The Harvard study is epidemiological, the kind of study which analyzes large populations and their health outcomes. Because the facts cannot be precisely measured, as it would be in a clinical study -nobody is weighing and measuring the foods people are eating, their body weights, or their lifestyle patterns – the conclusions which can be made are limited. This is true for many reasons. First, there are no “controls” in the study; making it difficult to tease out confounding variables having an effect beyond the particular foods being studied. What I mean is: eating certain foods is associated with specific behavior patterns, so it’s impossible to determine if the effect (weight loss/gain) is due to the food or the behavior pattern. For instance, studies of whole-grain eating find it is a “marker” for engaging in many healthy behaviors. People who eat whole grains are more likely to exercise and eat more vegetables. SO when epidemiological studies find whole grain- eaters are healthier, one must ask: is the effect due to eating whole grains or the lifestyle associated with eating whole grains? The only way to answer this question is, once the epidemiological data is observed, to take the observations into a lab and do a controlled clinical study. The clinical study would need to control for everything – exercise, diet, body weight, etc – and change only whether people are eating refined or whole grains, to determine if the health effect is due to the whole grain eating or the lifestyle.

POTATOES

The Harvard study found potato-eating associated with weight gain. The researchers warned against eating potatoes, attributing the weight gain to the rise in blood sugar caused by potatoes.

I am not quite convinced. Why?

First, many foods cause rises in blood sugar – including whole wheat bread and whole grain cold cereals. But they aren’t associated with weight gain, in fact, quite the opposite.

Second, in America, most potatoes are eaten as french fries or potato chips, and these are very fattening versions of potatoes. So, the way potatoes are cooked – not the potato itself – may be why Harvard’s epidemiological study found potato-eating is associated with weight gain. This argument points to excess calories as a factor.

Also, and this may be an important factor explaining why potatoes are associated with weight gain. When people eat french fries, they are usually eating hamburgers and hot dogs alongside.  Not only that, the beverage they’re drinking is SODA (a known contributor to obesity in adults and children). Therefore, instead of the potatoes causing the problem, could it be the meal pattern or high calorie lifestyle associated with people who eat french fried potatoes? In the United States, french fries are eaten together with fattening, unhealthy foods, known to be correlated with increased weight, diabetes, heart disease, you name it. Same with potato chips. People who regularly eat french fries, potato chips, and sodas also eat other fattening and unhealthy foods. In fact, studies show soda-drinking, for instance, is another “marker”  but this time, for engaging in unhealthy behaviors like smoking and being sedentary. These confounding variables could influence the study’s results.

This brings me to the last piece of evidence – and what convinces me the most – that potatoes do not a cause weight gain:  SWEDEN

In Sweden, people are no fatter than Americans, in fact, they’re slimmer. But, they eat potatoes every day, and often more than once a day. But when Swedes eat potatoes (and I’m sure of this as I am a Swede and visit often), they eat them in small portions, they’re boiled, topped with a little butter (oops), alongside FISH. Not burgers, not fried fish, just grilled, steamed, cured, smoked, or sauteed FISH.

So, if eating potatoes in Sweden is not associated with weight gain, could it be because the potatoes are cooked in a healthier way than in the United States and the meal pattern is a healthier one?  1) the potatoes are boiled, not fried, 2) the potatoes are eaten in smaller, more reasonable portions, and 3) the potatoes are more often eaten together with other healthy foods, such as fish – not burgers and sodas.

And, how do you explain all those poor, skinny Irish and Russians – heck, anyone living in the northern parts of the world – people who subsisted on and depended on potatoes as their only vegetable for centuries. Why didn’t the potatoes make them fat?

Do I believe potatoes are a wonder food? No. But I also do not believe potatoes are  “POISON,” as some commentators have stated.

Should you be eating larger portions of watery vegetables and smaller portions of starchy vegetables, such as potatoes? Yes.

Do I occasionally enjoy French Fries and Potato Chips, known to be fattening, unhealthy foods? Yes I do.

Do I eat French Fries and Potato Chips on a regular basis? No, I do not. Do I wish I could?
Yes I do, but I’d rather be healthy and slim.

NUTS

People eating nuts were more likely to have lower body weights, according to the Harvard Study. Their explanation is that nuts are satiating; they make us feel full, inferring that they lead to eating fewer calories overall. Clinical studies have found years ago that adding nuts to meals, especially breakfast, decreased overall calorie intake, making weight loss easier. This is one reason why I have been encouraging nut-eating for many years. Also, we’ve known for quite a while that nut-eaters around the world have fewer heart attacks and are healthier in other ways.

Does this mean you cannot gain weight eating too many nuts? No. Plenty of people eat too many nuts and can become overweight because of it. Nuts are healthy, but fattening little morsels. One ounce, or a small handful, contains about 180 calories. This is why I recommend most people eat one ounce per day. But if weight is not an issue, two ounces a day – or more, if you can afford the calories, is fine – and is even heart healthy. When I work with people wanting to gain weight healthfully, I advise snacking on nuts!

Are certain nuts better than others? I’m not convinced of this. Every time a new study comes out about a nut – any nut – it’s positive news. Certain nuts, though, are more commonly eaten, have a bigger consumer base, and more money to fund scientific studies. This may be why you hear about some nuts over others. It is also a very expensive and time-consuming process for a food to be approved for a health claim on a food label. So, only certain nut growers can afford to put health claims on their labels, and educate you about their health benefits.

While you already know each nut has a different look and flavor, each nut also has its own unique nutritional characteristics. For instance, almonds are the highest in protein and Vitamin E, and the lowest in artery-clogging saturated fat. Walnuts are the only nut with omega-3-fatty acids. Pecans have the highest antioxidant content. Pistachios contain lutein, a compound which may significantly improve eye health.

Bottom Line: Eat nuts every day.
They’re good for you and may help you eat fewer overall calories because they’re so satiating!
Yes, calories matter: So, stick with just one or two ounces, if weight is an issue. If not, eat more.

YOGURT

"Yogurt Spinach Dip" from "Diet Simple"

The study found yogurt-eating associated with lower body weights. Whole civilizations have known about yogurt’s health benefits for thousands of years.

When my mother was recovering from hip replacement surgery I advised her to live on yogurt, fruits and vegetables for healing AND to prevent weight gain from being immobile. It worked. She healed very quickly and lost a little weight at the same time. She was thrilled. I’ve repeated the same advice to my clients, when appropriate, and they’ve been thrilled with the results, too.

Yogurt has many positive qualities. I’m convinced: Yogurt is a Superfood; it may be one of the best overall foods you can eat. Yogurt creates a natural way to boost your immune system by providing probiotics which  increase the healthy bacteria in your gastrointestinal tract, according to my friend and colleague, Jo Ann Hattner, MPH, RD, in her book, “Gut Insight.”

Probiotics are live bacteria that promote digestive health. As we age, it is thought that bacterial populations in our gut change – resulting in increased harmful, disease-causing bacteria and fewer protective bacteria.   When you add probiotics you repopulate the gut with beneficial bacteria that protect against infection-causing toxins.

You also improve colon health by lowering pH of the colon, so it’s receptive to the beneficial bacteria and detrimental to the disease-causing bacteria, you protect the intestinal lining, and strengthen immunity.  Exciting research is evolving on the health benefits of probiotics.

But correlating yogurt with lower body weights is complicated. Do you believe people who regularly eat french fries, potato chips, burgers and sodas eat much yogurt? I don’t think so. This is another case where lifestyle probably plays a huge role and why Harvard’s epidemiological study found yogurt was associated with lower body weights.

While it may be true that yogurt has health benefits causing leanness, this hasn’t been proven conclusively in clinical studies yet. There have been studies showing dairy foods are very satiating… That is, when you eat yogurt, you feel full in relation to the calories. And when you feel extra satiated by something, such as yogurt or nuts, it helps you eat fewer overall calories for the day. There is some evidence that the protein in yogurt may be especially high quality, spare lean muscle (and bone), and increase metabolism, thereby making weight loss a little easier. Diary products may also contain other bioactive compounds contributing to leanness. The Harvard researchers speculated the probiotics in yogurt may be responsible for the weight benefit. All of these reasons could be significant. But, the most significant factor probably is: Yogurt-eaters are more likely to live a healthy lifestyle, exercise, and eat other healthy foods.

My clients, family and friends have known this for years. Why? I love keeping up with the science and keep myself and them informed.

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New Study Finds Certain Foods Lead to Living Longer

Eating Healthier Means Living Longer

According to New Study in the Journal of the American Dietetic Association

Researchers found that diets favoring certain foods were associated with reduced mortality.

The leading causes of death have shifted from infectious diseases to chronic diseases such as cardiovascular disease and cancer. These illnesses may be affected by diet. In a study published in the January 2011 issue of the Journal of the American Dietetic Association, researchers found that diets favoring certain foods were associated with reduced mortality. Scientists investigated empirical data regarding the associations of dietary patterns with mortality through analysis of the eating patterns of over 2500 adults between the ages of 70 and 79 over a ten-year period.

By 2030, an estimated 973 million adults will be aged 65 or older worldwide. The objective of this study was to determine the dietary patterns of a large and diverse group of older adults, and to explore associations of these dietary patterns with survival over a 10-year period. A secondary goal was to evaluate participants’ quality of life and nutritional status according to their dietary patterns.

By determining the consumption frequency of 108 different food items, researchers were able to group the participants into six different clusters according to predominant food choices:

• “Healthy foods” (374 participants)
• “High-fat dairy products” (332)
• “Meat, fried foods, and alcohol” (693)
• “Breakfast cereal” (386)
• “Refined grains” (458)
• “Sweets and desserts” (339).

The “Healthy foods” cluster was characterized by relatively higher intake of low-fat dairy products, fruit, whole grains, poultry, fish, and vegetables, and lower consumption of meat, fried foods, sweets, high-calorie drinks, and added fat. The “High fat dairy products” cluster had higher intake of foods such as ice cream, cheese, and 2% and whole milk and yogurt, and lower intake of poultry, low-fat dairy products, rice, and pasta.

The study was unique in that it evaluated participants’ quality of life and nutritional status, through detailed biochemical measures, according to their dietary patterns. After controlling for gender, age, race, clinical site, education, physical activity, smoking, and total calorie intake, the “High-fat dairy products” cluster had a 40% higher risk of mortality than the “Healthy foods” cluster. The “Sweets and desserts” cluster had a 37% higher risk. No significant differences in risk of mortality were seen between the “Healthy foods” cluster and the “Breakfast cereal” or “Refined grains” clusters.

Photo by Polly Wiedmaier

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Grains of Truth

Original Content, The Washington Post

In the world of nutrition there seems to be no shortage of complexity and confusion. But I’ve found that simple and straightforward solutions are often strikingly successful. In no area is this more true than the remarkable power of whole grains.

Over the years, countless clients of mine have struggled with various gastrointestinal complaints such as constipation or irritable bowel syndrome. Many have come to me after trying costly medications, usually with little relief.

In most cases, symptoms disappeared once they began increasing their fiber intake by eating adequate amounts of whole-grain foods. Some of my clients even teasingly call these foods their wonder drug.

But while it’s true that whole grains are valuable for their fiber content, their benefits are much more vast. Whole grains play a profound role in health. A growing body of research shows whole grains — wheat, oats, rice, rye and corn, for example, may help keep body weight down and prevent diabetes, heart disease and some cancers.

The importance of whole grains in health came to light in the 19th century, when refining grains became popular — and its negative consequences were learned. In Asia, chickens were cured of symptoms of a human illness called beriberi, characterized by muscle wasting and nerve degeneration, when they were fed the discarded part of polished white rice. It was later found that the parts discarded during the refining process contain the essential nutrient, thiamin (a B vitamin) necessary to prevent beriberi.

In 1975, researchers Dennis Burkitt and Hugh Trowell published a book of scientific observations comparing the diet of Africans eating their native whole grains versus North Americans and British eating their diet of highly refined carbohydrates. The researchers described for the first time the role that whole, unrefined foods play in reducing coronary heart disease, diabetes and cancer. Since then, numerous other research studies have chronicled the effects of whole grains on human health.

A whole grain has three parts: bran, germ and endosperm. The bran and germ contain fiber, Vitamin E, B vitamins (thiamin, niacin, riboflavin and pantothenic acid) minerals (calcium, magnesium, potassium, phosphorous, sodium, selenium and iron), protein, essential oils, antioxidants and phytochemicals (plant substances that may protect health). The endosperm contains mostly starch with a little protein and very few nutrients. When a grain is refined, turning whole wheat flour into white flour or brown rice into white rice, only the nutrient-poor endosperm is left. The riches found in the bran and germ are lost.

Food manufacturers attempt to make up for the loss in nutrients by enriching refined grains (those found in breads, pasta, rice and cereals, for instance) with some essential nutrients, such as B vitamins and iron.

But overwhelming scientific evidence has found major health differences in people who eat more whole grains compared with people who eat refined grains, proving enrichment doesn’t make up for the difference:

• Whole grains are our major source of fiber. The grain’s outer layer (the bran) keeps us regular and helps prevent hemorrhoids, diverticulitis, and reduces risk for ulcerative colitis (Crohn’s disease).

• Whole-grain intake is strongly correlated with reduced cardiovascular disease. This is partly explained by the soluble fiber in grains (oats, rye and barley have the highest levels), which is associated with cholesterol lowering. But other substances in grains, such as antioxidants like Vitamin E, also play a role.

• People who eat more whole grains also have lower body weights, according to epidemiological research. This is attributed to the fiber, which promotes feelings of fullness in foods that are generally low in calories.

• Many studies have shown a strong link between whole-grain intake and reduced incidence of type II diabetes. This may be partly because the fiber in whole grains slows down stomach emptying, causing a lower rise in blood glucose and insulin. Also, whole grains contain nutrients such as Vitamin E and magnesium, which may help improve insulin sensitivity.

• This research is less consistent, but whole grains may also help prevent cancers, especially of the intestinal tract and maybe even breast cancer. Several theories have been put forth explaining the mechanisms. For one, the fiber speeds intestinal transit, which reduces exposure to potential carcinogens. Also, antioxidants enter the circulation through colon cells, providing long-term antioxidant protection through the entire digestive tract, according to Joanne Slavin, a professor in the department of food science and nutrition at the University of Minnesota in St. Paul. Ninety percent of a grain’s antioxidants aren’t released until they get to the colon, the last stage of digestion, where they may provide maximum protection against cancer.

Interestingly, grains are still a mystery to researchers. They are so complex and full of a multitude of different compounds, scientists are largely unsure of what components of the grain are responsible for the benefits.

“We’re not sure if the benefits are from the fiber or the phytochemicals,” says Simin Liu, assistant professor of medicine and epidemiology at Harvard. “In my opinion, it’s the thousands of phytochemicals in whole grains which produce most of the benefits.”

To prove his point, Liu points to a four-year National Cancer Institute-funded study of high-fiber cereals in which wheat bran was added in the processing as opposed to naturally occurring in a whole grain. Researchers were surprised to find the high-bran diet did not prevent colon polyps, often a precursor to cancer.

“The data doesn’t support the claim that added bran fiber or fiber supplements make a positive difference in colon cancer, which is why I like to use the term ‘whole grain foods’ instead of fiber. The data only point to whole foods,” says Liu.

But while whole grains provide this wide array of health benefits, most Americans don’t take advantage of them.

“American adults eat six to seven servings of refined grains but only one serving of whole grains a day, with children eating less than one serving — well below U.S. Dietary Guideline recommendations of at least three servings,” says Slavin.

While science continues its search for the answers, I recommend you switch from refined-grain products to whole-grain products. Instead of white bread or crackers, choose whole wheat, whole rye or whole grain breads and crackers. Instead of white pasta or white rice, choose whole wheat pasta or brown rice or cereals made with whole oats or whole corn. Try unusual grains such as bulgur (cracked whole wheat), whole wheat couscous or exotic grain-like substances such as quinoa and amaranth.

But looking for whole-grain foods in your supermarket can be challenging. Many “whole wheat” or “multi-grain” breads, for instance, are made predominantly of white flour, even though the label may say “wheat flour.” Be sure the first ingredient on the nutrition label of your pasta, cereal, crackers or bread is a “whole” grain such as whole wheat, whole oats or whole rye. Also look for a whole-grain product containing three or four grams of fiber per one ounce (28 grams) or per 80- to 100-calorie serving. That signifies that the grain is likely in its most natural state.

Katherine Tallmadge is a Washington nutritionist and author of “Diet Simple” (Lifeline Press, 2004). Send e-mails to her at food@washpost.com.

Grain Guide

The grain family includes barley, bulgur, corn, millet, oats, rice, rye and wheat. Amaranth, buckwheat, and quinoa belong to a different botanical family. But they all contain protein, B vitamins, minerals and fiber, as well as antioxidants. Though corn, oats, rice, rye and wheat are relatively easy to find and cook, other of these healthful ingredients may require a search and some guidance before cooking:

AMARANTH This tiny seed, often found in health food stores, can be used to make flour or pasta. Add the seeds to your bowl of cereal, rice or stir-fry.

BARLEY This versatile grain makes a great pilaf or risotto; use the cooked leftovers in a salad, stir-fry or tuna salad.

BUCKWHEAT The seeds of the plant are used to make buckwheat flour, the basis of blini. Buckwheat groats are the hulled and crushed kernels of the seed and are usually cooked in a manner similar to rice. When the groats are toasted, they are called kasha. Add buckwheat to soups, stew, meatloafs or hamburgers. Cook buckwheat groats for a hot breakfast cereal.

BULGUR (also BULGHUR) Made from whole-wheat berries that are steamed, partially de-branned, dried and crushed or cracked, bulgur wheat is available in coarse, medium and fine grinds. A staple of the Middle Eastern diet, it is seen in salads such as tabbouleh or stews. It can also be cooked like a rice pilaf.

MILLET Cracked millet can be cooked like couscous; another variation, pearl millet, can be cooked like rice or a hot breakfast cereal. Millet flour is used in roti, an Indian flatbread.

QUINOA Pronounced “KEEN-wah,” this grainlike product is often found in health food stores. The grain, which must be simmered, has a delicious roasted flavor and can be added to vegetable dishes or rice. Quinoa flakes, a hot cereal similar to oatmeal, make a hearty breakfast.

— Katherine Tallmadge

© 2004 The Washington Post Company

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