Food Guide Pyramid Criticised
Regular cereal box readers likely recognize the Food Guide Pyramid, a graphic designed by US Department of Agriculture (USDA) as an easy-to-follow guide to healthy eating. The pyramid purposefully includes widely available foods that most Americans are familiar with. Pyramid designers thought that by featuring common foods, more people would use the pyramid to actually achieve a balanced diet. But some researchers are not happy with the nutrition message of the USDA pyramid. They think that the government's recommendations rely too heavily on animal foods, refined grains, and give "heart healthy" vegetables oil too little recognition. Harvard University's Dr. Walter Willet is one critic who has gone a step further; he's devised his own pyramid that realigns the concept of a healthy diet. His version, which represents the most recent advances in research on nutrition and health, looks like the following:
#1: Build Your Own Base
Daily exercise and weight control are the foundations of Willett's pyramid. We now know that many chronic disease such as diabetes, heart disease, obesity and osteoporosis that are plaguing Americans are a direct result of inactivity. It is the scientific consensus that we should all center our days around being active in ways that we enjoy-walking the dog, going for a bike ride, or joining a gym. It's not so much intense exercise that helps maintain good health as it is leisure activities that we enjoy. The bottom line is that it won't matter how well we eat if we don't get moving.
#2: Hello FAT, Goodbye PASTA!
Next in line for better health, are good fats and whole grains. The bread, cereal, rice and pasta that appear at the base of the original pyramid are all high in carbohydrates, the body's primary source of fuel. In addition, grain products are high in fiber, minerals, and other vitamins. But, the USDA Pyramid ignores the fact that the most common grain products on grocery store shelves-white bread, crackers, pasta, and cereal-- are made with refined flour that has lost nutrients during processing. The USDA Pyramid fails to distinguish between a plateful of pasta and bowl of whole grain oats. Some scientists think that a diet high in refined grain foods like white rice, potatoes, and products made from white flour, may actually be fueling the rapid increase in diabetes, heart disease, and obesity in this country. If so, then it's not the carbohydrates themselves that are responsible for any ill-health effects, but the form that they come in. One theory, championed by Tufts researcher, Susan B. Roberts, hold that refined carbohydrates cause a rapid rise in blood insulin-a hormone that keeps blood sugar levels in control. Many researchers believe that consuming too much of these foods over time over-taxes our system and makes us more prone to diabetes and heart disease. Whole grain foods such as whole wheat, brown rice, or oatmeal, on the other hand, are good sources of fiber, which slows the release of carbohydrates into the bloodstream and keeps insulin levels from spiking. Keeping insulin on an even keel, say the scientists, is key to weight control. Whole grains also contain a whole slew of phytochemicals that experts believe help to maintain good health. And, believe it or not, Willet says that fat belongs at the very bottom of the pyramid, right next to whole grains. The USDA Pyramid places fat at the top, to be consumed in very limited quantities. But not all fats are the same. Saturated fats-from meat and dairy foods-can contribute to the development of heart disease. Vegetable oils such as olive and canola, on the other hand, may well deserve a prominent place in the American diet. These mono- and polyunsaturated fats are considered "heart healthy" because they do not raise blood cholesterol levels and may even help slow the progression of heart disease. This notion of good versus bad fats is supported by the fact that Mediterranean cultures who consume a high amount of plant oils and fatty fish have very little incidence of diabetes and heart disease.
#3: Vitamins, Minerals, Fiber, and Phytochemicals
As one might expect, once our basic energy needs have been met, the class of foods we should focus on come from the plant kingdom. Vegetables and fruits in abundance will provide essential vitamins and minerals and enough fiber and disease-fighting phytochemicals to help keep you healthy. Although five servings a day is the standard recommendation, no one will argue that the more you get, the better. In fact, Tufts scientist, Jim Joseph, recommends up to 9 servings a day to reduce the risk of cancer and other age-related diseases. To get the most from your servings choose leafy greens regularly, lots of berries, and shoot for maximum color diversity. Every color of fruit and/or vegetable will deliver unique health benefits.
Yep, that's right. Nuts and legumes go next. Not only do nuts provide high-quality protein, they also come packed with 'good' fats, i.e. fats that help lower 'bad' cholesterol. And beans are another good source of protein, with the added value of fiber, which helps to control appetite, may help reduce the risk of heart disease, and may even fight cancer.
#5: Fish, Poultry, and Eggs
The USDA Pyramid puts nuts, legumes, red meat, fish and eggs all in one category, which suggests that they are all equal. But, research shows that they are indeed very different. Unlike red meat, fish has almost no artery-clogging saturated fat, but it has lots of 'essential fats,' the kind of fats that help make important hormones that regulate body functions and may help prevent heart attacks. Eggs are also getting another look as a good source of protein-new research shows that an egg a day is not bad for your heart and egg yolks contain phytochemicals - lutein and zeanxanthin - that help fight age-related cataracts.
A growing school of thought in the nutrition community says that it's not necessary to rely solely on dairy foods for calcium, and points to evidence that many Americans' diets lack the minerals needed for calcium balance. According to research by Katherine Tucker of Tufts, if we focused more on whole foods, such as whole grains, legumes, and produce, we would create a positive mineral balance and easily meet our daily calcium needs. Not all plant foods contain calcium, though, so know some good alternative sources of calcium such as soy-based products and calcium-fortified orange juice before you ditch dairy from your diet.
Willett's revised pyramid lumps red meat, butter, white rice, white bread, potatoes, pasta, and sweets into one category at the very tip of the pyramid, only to be used sparsely. Red meat and butter contain a lot of harmful saturated fat, whereas potatoes, refined grain products and sweets contain 'empty calories' that may contribute to weight gain and diabetes. Keep in mind that not all scientists buy into the theory that potatoes and pasta are bad for you, but most agree that loading up on one kind of food, like pasta, while shunning other kinds of foods, like vegetables, is an unhealthy way to eat. Regardless of how they package it, though, their nutrition advice is basically the same: eat a diet high in fruits, vegetables, and whole grain foods, eat less red meat and more fish, choose low-fat dairy foods if you include dairy in your diet, and go with vegetable oils and spreads over animal fats like butter.
Valerie Green is a combined MS/MPH student studying Nutrition at Tufts' Gerald J. and Dorothy R. Friedman School of Nutrition Science and Policy.