It seems as though every day there is a new item in the news about what people should or should not eat in their daily diet. Sorting through all the valid information can be difficult, especially when there are claims to be made, products to be sold, and profit to be gained. As someone concerned about health and fitness, I wanted to do some research that gets back to the basics, is based on objective and rigorous scientific studies, and is uninfluenced by a desire for profit. I researched information provided by U.S. government health agencies to see what the current science and research has to say about proper nutritional guidelines and dietary fundamentals.
The U.S. Department of Health and Human Services publishes its “Dietary Guidelines for Americans” every five years, a document that provides general recommendations for keeping to a diet that provides the greatest nutritional benefits while reducing the health risks that come from unhealthy eating. I refer to the latest edition, as of the writing of this article, the “2010 Dietary Guidelines for Americans,” which can be read online from this U.S. Department of Health and Human Services website. This 95-page booklet is easy-to-follow, with information grouped into sections across six chapters, including “Balancing Calories to Manage Weight,” “Foods and Food Components to Reduce,” and “Foods and Nutrients to Increase.” The dietary guidelines also includes tables for determining individual daily calorie needs, charts of nutritional information, and reminders about proper food handling.
I read through this document because I wanted to become more knowledgeable about proper nutrition, to assess my current diet to see what I was doing right and what I could improve upon, and to make real and immediate changes that would help make me more healthy through better eating. I have summarized what I’ve learned into six articles in this series on “Dietary Guidelines.” I certainly recommend that you read the entire “Dietary Guidelines for Americans”on your own as well as conduct further research into more healthful eating, but at the same time I know time is precious and I imagine that you want to get started right away in making positive changes to your diet.
Besides the “2010 Dietary Guidelines for Americans,” these articles contain additional facts and suggestions from the excellent and comprehensive book, “American Dietetic Association Complete Food and Nutrition Guide” by Roberta Larson Duyff (3rd edition, 2006).
This first article in my “Dietary Guidelines” series covers information primarily from chapter 2 of the dietary guidelines, “Balancing Calories to Manage Weight,” which provides advice in how to lose weight and maintain a proper weight and also explains the macronutrients.
If we could summarize the dietary guidelines’ advice into one simple sentence it is this: People should strive to consume more nutrient-dense foods and beverages to ensure proper nutrition within calorie limits. We’re all aware of the expanding waistline in the United States, but in case we need to be reminded the figures are about 72% of men, 64% of women, and 32% of children are above their ideal weight ranges, according to the dietary guidelines. Ironically, though, despite all these excess calories consumed, many individuals are still not getting the recommended nutrition in their diets. The chief culprit is the consumption of calories from foods and beverages with too much solid fat and added sugars, which provide plenty of calories but relatively few nutrients.
Balancing Calories to Manage Weight
Much of chapter 2 in the dietary guidelines describes how individuals can reduce their weight and maintain a proper weight over time. People can do this by paying a closer attention to how many calories they need a day (calories “in”) with how much calories they burn through normal daily functions as well as through physical activity (calories “out”).
The specific amount of daily calorie needs for an individual varies by gender, age, and how physically active the person is. Page 78 of the dietary guidelines includes a helpful chart for instantly determining one’s specific daily calorie needs. Daily calorie needs can range from 1,000 to 2,000 calories a day for children; 1,400 to 3,200 calories a day for adolescents; 1,600 – 2,400 calories a day for adult women; and 2,000 to 3,000 calories for adult men. Note that 1 pound is equal to 3,500 calories.
As long as one eats within the recommended calorie limits, the number of meals consumed per day is not important. Some people may wish to eat 5-6 smaller meals instead of the customary 3 meals a day; either way can be equally as healthy as long as the overall daily calorie amount is the same. An individual who desires to lose weight might consider lowering his or her daily calorie intake by about 250-300 calories a day (but should not drop below 1,600 calories a day). Another consistent finding among those who maintain proper weight is to not skip breakfast.
Of course the dietary guidelines’ main focus is to recommend proper nutrition, but it is also quick to point out the important link between regular physical activity and managing weight. As a general guideline, adults should get at least 30 minutes of physical activity a day, and children and adolescents should strive for at least 60 minutes a day. Refer to the U.S. Department of Health and Human Services’ 2008 Physical Activity Guidelines for Americans for important exercise and fitness fundamentals.
Now let us review the three main “building blocks” of food, the so-called macronutrients: carbohydrates, protein, and fats.
Carbohydrates, your body’s main source of energy, can come from two sources: starches (also called complex carbohydrates) and sugars. Fiber is also considered a carbohydrate, for even though it cannot be digested by the body and is technically not a nutrient, it does help promote good digestion and has other key benefits. The dietary guidelines recommends that individuals get 45% to 65% of their daily calorie needs from carbohydrates. Obtaining enough carbohydrates ensures that the body does not have to start using protein to provide energy. Contrary to some popular opinion, carbohydrates themselves do not promote weight gain; it is consuming too many calories from any source that causes weight gain.
Interestingly, because the body breaks down all carbohydrates (except fiber) into simple sugars during digestion, it can receive its carbohydrate intake equally from starches or sugars. However, the dietary guidelines recommends that individuals choose carbohydrates from naturally occurring sources whenever possible because of the other nutrients these foods provide. Good naturally occurring carbohydrate sources include fruits and vegetables, whole grains, and beans and peas.
At least half of daily grain consumption should come from whole grains rather than refined grain products. Some good whole grain sources include whole wheat, brown rice, whole oats, oatmeal, quinoa, and whole rye. A “whole grain” simply means a grain that includes the entire edible part, as opposed to a “refined grain,” which removes a portion of the grain.
Foods high in fiber, such as legumes, may contribute to weight control, as these foods tend to be lower in calories, fat, and added sugars. Since fiber itself is not digested, it does not provide any calories. In addition, the added bulk of fiber-rich foods means they take longer to chew and therefore may slow down eating, contributing to fewer calories consumed and providing a sense of fullness, according to the American Dietetic Association.
Individuals should limit their consumption of food and beverages that contain added sugars, because this can quickly lead to weight gain. Note that “natural”-looking sugars such as raw sugar, date sugar, honey, or maple syrup are not any more healthful than other types of sugars.
Proteins, part of amino acids, help build, repair, and maintain body tissues. They can also provide energy when there is a lack of carbohydrates. Although the body can produce “nonessential” amino acids, it cannot make “essential” amino acids and therefore must acquire them from food sources. The dietary guidelines recommends that 10% to 35% of adults’ daily calorie needs come from protein sources. Depending on an individual’s daily calorie needs, approximately 5-7 ounces a day of protein may suffice.
The dietary guidelines recommends obtaining protein from a variety of sources, both animal and plant. Individuals should consider especially seafood, lean meat and poultry, eggs, beans and peas, lentils, soy products, and unsalted nuts and seeds as excellent protein contributors.
Eggs are excellent sources of protein, with just one egg supplying about 10% of daily protein needs, and they are also low in fat. They do, however, have high amounts of cholesterol, but this can be minimized by using just the egg white (which has no cholesterol) or a reduced-cholesterol egg substitute.
Foods high in protein also tend to be high in other valuable nutrients, including iron, zinc, magnesium, vitamin E, and B vitamins.
Fats are essential nutrients for the body and are especially important to a child’s growth. Fats are the densest energy source of all macronutrients and serve a vital function by carrying the fat-soluble vitamins A, D, E, and K–in addition to phytonutrients–in the bloodstream. The dietary guidelines recommends that adults receive 20% to 35% of their daily calories from fats. Visually speaking, for an individual requiring 2,000 calories a day, this equates to 6 teaspoons of oil a day.
It is important to take note of the type of fat consumed, because some kinds of fat are recommended and some are discouraged, mainly due to the way they affect cholesterol. Fats can be saturated, monounsaturated, or polyunsaturated. The more “saturated” the fat the more solid it is at room temperature. Trans fatty acids (most of which are solid at room temperature) is another category of fats that has undergone a special process called hydrogenation.
The dietary guidelines calls for individuals to reduce their intake of saturated fat and trans fatty acids as much as possible, while replacing them with the more healthful monounsaturated and polyunsaturated fats. Animal sources of fat (except seafood) tend to be higher in saturated fat than plant sources (with one exception being coconut oil, which is high in saturated fat).
Americans’ elevated consumption of saturated fats and trans fatty acids is such a concern that the dietary guidelines lists these fats in a separate chapter called “Foods and Food Components to Reduce.” Not only are individuals who consume a high-fat diet at risk for higher cholesterol levels but also heart disease, obesity, and colon and prostate cancers.
Both monounsaturated and polyunsaturated oils have been linked to higher levels of HDL cholesterol (the “good” cholesterol) and lower levels of LDL cholesterol (the “bad” cholesterol). Good sources of monounsaturated fats include olive oil and canola oil; while good sources of polyunsaturated fats include corn, soybean, sesame, safflower, and sunflower oils.
A special kind of polyunsaturated fat called omega-3, which is found mainly in seafood such as salmon and tuna, has been linked to thinner blood and helping to prevent blood platelets from forming on artery walls. The dietary guidelines recommends that individuals incorporate seafood into their diet regularly, consuming about 8 ounces a week, to take advantage of the heart-healthy benefits.
U.S. Department of Agriculture and U.S. Department of Health and Human Services. ” Dietary Guidelines for Americans, 2010 .” 7th Edition, Washington, DC: U.S. Government Printing Office, 2010. PDF.
Duyff, Roberta Larson and American Dietetic Association. “American Dietetic Association Complete Food and Nutrition Guide.” 6th Edition. Hoboken: Wiley & Sons, 2006. Kindle.