These 5 Simple Nutrition Guidelines Are Undisputed By Experts and Research

Getty Images

There's a tremendous amount of nutrition information out there that's constantly swirling on the internet, in your gym locker room, and over your dinner table. One day you hear that a food is "bad" for you, while the next it's "good" for you. A new fad diet pops up every few months, each one hinging on completely a different philosophy. Is fat evil or are carbs the worst? Should you count macros or the hours between meals? Sip coffee daily or skip caffeine altogether?

It seems that the world of nutrition is ever-changing, and it's rather tough to keep it all straight. The truth is that restrictive dieting isn't sustainable in the long term and as such, likely won't give you the results you're after — but building healthy eating habits for life will serve you well. And the basics of how to eat healthy are really, well, basic.

If you're ready to learn how to eat healthy and cut through the nutrition B.S., read on for five nutrition guidelines that are undisputed by nutrition experts and backed up by scientific research. These are the nutrition principles you can always count on to be true — and turn to in learning how to start eating healthy and maintaining that lifestyle for good — no matter what other nutrition buzz gains favor or gets thrown your way.

1. Eat Plenty of Fruits and Vegetables

Based on the United States Department of Agriculture's Dietary Guidelines of Americans, adults should consume at least 1 1/2 to 2 cups of fruit and 2 to 3 cups of vegetables per day as part of a healthy eating pattern; however, only 1 in 10 Americans meet this daily recommended amount of fruit and vegetable consumption, according to the Centers for Disease Control.

Eating plenty of fruits and vegetables is "indisputable and everyone should be doing it," says Lisa Young, Ph.D., R.D.N. nutritionist in private practice and adjunct professor at NYU. Study after study backs it up, showing that there are countless benefits to eating fruits and vegetables. "Eating an adequate amount of fruits and vegetables is linked to a slew of positive outcomes, and the benefits can't be matched by simply taking a pill," adds Lauren Manaker M.S., R.D.N., L.D., author of Fueling Male Fertility. "These foods are not only loaded with vitamins and minerals, but they're also packed with antioxidants, fiber, and other beneficial components."

Some of those other beneficial components include phytonutrients, natural plant compounds that help fight and prevent disease, many of which act as antioxidants. Fruits and vegetables also contain fiber, which has a multitude of health benefits including increasing satiety and decreasing the risk of several diseases like heart disease, type 2 diabetes, and some forms of cancers. Research also concludes that when you eat fruits and vegetables that are prepared without added sugar or saturated fat (e.g. butter), it can help improve the measured quality of your diet, meaning you get more of the nutrients your body needs and less of the ones you already get a lot of. To top it off, other research shows that eating more fruits and vegetables can make you happier, too.

In addition, "when you eat more fruits and veggies, you likely eat fewer unhealthy foods," says Young. She uses this guideline when working with clients because, "as a nutritionist, I like to focus on foods you can add to your diet as opposed to foods you should take away. And as a portion-size advocate, it's not always about eating less, but about eating better." (See: Why Eating More Could Be the Answer to Losing Weight)

2. Get Enough Fiber

Only about 5 percent of the U.S. population meets the recommended amount of dietary fiber, according to a 2017 study published in the American Journal of Lifestyle Medicine, and that's why it's been categorized as a nutrient of public health concern by the USDA. The American Heart Association recommends eating a total of 25 to 30 grams per day of fiber from food (not supplements), while the Academy of Nutrition and Dietetics recommends between 25 to 38 grams per day, depending on gender. On average, Americans only eat about 15 grams.

If you're new to learning how to eat healthy, the recommended amount of fiber may seem like an overwhelming amount, says Emily Rubin, R.D., L.D.N., director of clinical dietetics at Thomas Jefferson University Division of Gastroenterology and Hepatology in Philadelphia. That's why "fiber supplements such as pills and powders may be recommended by your physician or dietitian," she says. However, "these sources of fiber are not enough to meet the daily recommendations. You also need to include whole foods like vegetables, fruits, beans, whole-grain breads, cereals and pastas, and fruit." (See: How to Eat More Fiber)

The health benefits of fiber have been demonstrated in many studies — namely, that eating a diet high in fiber is associated with a reduced mortality risk for heart disease and other chronic diseases that plague Americans. "Many studies have linked higher intakes of dietary fiber to reduced risk of developing several chronic diseases, including cardiovascular disease, type 2 diabetes, some cancers, and gastrointestinal diseases/conditions," adds Rubin. In addition, "fiber helps maintain digestive health, lower cholesterol, stabilize blood sugar, and keep weight in check. Fiber also helps you feel full so you don't overeat." Young says that when her weight loss clients increase their fiber intake, they tend to feel more satisfied and are better able to limit eating junk food.

3. Stay Hydrated

Up to 60 percent of the human body is water, according to the U.S. Geological Survey. As such, you need fluids to maintain every function in your body, including everyday duties performed by the heart, brain, and muscles. Fluids in your body also help carry nutrients to your cells, and can also prevent constipation. Not to mention, dehydration can lead to unclear thinking, mood change, kidney stones, and cause the body to overheat, according to the CDC.

As for how much you should be drinking? That can get confusing. Your daily fluid intake (or total water) is defined as "the amount of water consumed from food, plain drinking water, and other beverages," according to the CDC. The recommended amount can vary based on age, gender, and if someone is pregnant or nursing. One estimate from the Academy of Nutrition & Dietetics says women need approximately 9 cups of water and men need 12.5 cups of water per day, plus the water you get from foods in your diet. Besides plain water, you can get fluids from eating plenty of fruits and vegetables and other foods that naturally contain water (such as salads and applesauce), according to Harvard Medical School. Even 100-percent fruit juice, coffee, and tea count towards your daily recommended fluid intake. Many experts and the CDC agree that drinking water is a good way of getting fluids since it's calorie-free.(Here's everything else you need to know about hydration.)

4. Eat a Variety of Foods

It's widely accepted that bodies need a variety of nutrients in order to stay healthy. "Food has a lot to offer, but no single food has all the nutrients you need," says Elizabeth Ward, M.S., R.D., author of Better is the New Perfect, who recommends choosing an array of foods as part of a balanced diet. The AHA also recommends "eating the rainbow" of fruits and vegetables in order to get a variety of vitamins, minerals, and phytonutrients.

This concept also applies to a variety of foods including grains, nuts, seeds, fats, and more. The wider variety of foods you eat in each of the various food groups, the greater variety of nutrients you'll take in. You need each of these nutrients so that different systems in your body can function well. For example, the potassium found in bananas and potatoes helps with muscle contractions, including the contractions of your heart. Magnesium, found in green leafy vegetables such as spinach, helps regulate numerous body functions including blood pressure and blood glucose control. (Related: A Guide to the Essential Nutrients — and Why Your Body Needs Them)

Research also backs up the health benefits of eating a diverse diet. A 2015 study published in the Journal of Nutrition found that when 7,470 adults ate a greater healthful variety of foods, they lowered their risk of metabolic syndrome (a cluster of conditions that occur together and increase your risk of heart disease, stroke, and type 2 diabetes). In addition, a 2002 study published in the International Journal of Epidemiology found that increasing the variety of healthy foods you consume can increase your life span. Although everyone may not agree on the statement that increasing a healthy variety of foods will automatically increase your lifespan, researchers concluded that if you increase the number of healthy foods in your diet regularly, you also tend to decrease the number of less healthy foods eaten on a regular basis.

Stephanie Ambrose, M.S., R.D.N., L.D.N., C.P.T. instructor of dietetics at Nicholls State University in Thibodaux, Louisiana and owner of Nutrition Savvy Dietitian, explains how she carries out this recommendation with her clients who are learning how to eat healthy: "Whenever I counsel patients, I stress the importance of consuming actual fruits and vegetables and switching up the fruits and vegetables that you eat. If you normally grab a banana for breakfast every morning, try switching it up to another fruit that you also enjoy to gain the benefits of different antioxidants and vitamins." Same goes if you typically eat a salad with the same vegetables every day; try to swap up your vegetable choices day to day or week to week. Instead of always choosing chicken, swap in seafood at least twice a week, which can provide beneficial omega-3 fats, says Ward.

5. Minimize Overly Processed Foods

If you've been trying to learn how to eat healthy, you've likely heard that processed foods aren't good — but processed foods, in general, are not the issue here. A bag of pre-washed salad greens, a slice of cheese, and a can of beans can all be considered processed, to a degree. It's the overly processed foods that provide few good-for-you nutrients and many nutrients you likely already over-consume.

For example, most cookies, donuts, and cakes are high in calories, saturated fat, and added sugar and provide little to no vitamins and minerals. A higher intake of saturated fat has been linked to a higher risk of heart disease. For that reason, the AHA recommends "replacing foods that are high in saturated fat with healthier options can lower blood cholesterol levels and improve lipid profiles." Also, consuming too much added sugar has also been associated with health issues, such as weight gain and obesity, type 2 diabetes, and heart disease, according to the CDC. The 2020-2025 Dietary Guidelines for Americans recommend eating no more than 10 percent of total calories (or about 200 calories) from added sugar — a recommendation that almost all Americans go over. (See more: Everything You Need to Know About the 2020-2025 Dietary Guidelines for Americans)

A good rule of thumb for how to eat healthy: "Choose foods that are the closest to their original forms, such as fresh meat, chicken, and fish and fruits and vegetables for the most nutrients and the least added fat, sodium, and sugar," says Ward. It's really that simple.