Expert Questions and Answers
Browse common nutrition questions answered by Nutrition.gov's Registered Dietitians. Looking for other information on healthy eating? Ask your questions here.
Are natural supplements good for you?
Some individuals consider herbal or botanical supplements to be “natural.” However, herbal or botanical supplements are not proven to be safer. All dietary supplements, including herbal remedies, are not required to be reviewed for safety and effectiveness before being sold. Read 5 Tips: What Consumers Need To Know About Dietary Supplements from the National Center for Complementary and Integrative Health and talk to your doctor before starting any supplements. Find more information on Nutrition.gov’s Herbal Supplements page.
Where can I find information on types of dietary supplements?
Dietary supplements come in a variety of forms, including pills, liquids, and powders. You can learn about types of dietary supplements in the Dietary Supplements section on Nutrition.gov. Other reliable sources of information include:
- Herbs at a Glance (National Center for Complementary and Integrative Health)
- Botanical Supplement Fact Sheets (Office of Dietary Supplements)
- Dietary Supplement Fact Sheets (Office of Dietary Supplements)
- Vitamin and Mineral Supplement Fact Sheets (Office of Dietary Supplements)
Find questions to consider when evaluating supplements for safety in the Food and Drug Administration’s Tips for Dietary Supplement Users. We advise you to discuss all dietary supplements or alternative medicines with your doctor before taking them. Your doctor is familiar with your health status and can help you determine if the supplement is safe and may be helpful.
What are the risks and side effects of taking dietary supplements?
Companies are not required to prove dietary supplements are safe and effective before they are sold. That means it is possible for supplements to contain too much or too little of an ingredient or be contaminated with an unexpected ingredient. Find more information in the Food and Drug Administration’s Information for Consumers on Using Dietary Supplements resource. A variety of resources on the risks and safety of dietary supplements are also available on Nutrition.gov’s Safety and Health Claims page. If you experience a serious negative side effect from a dietary supplement, follow the steps on Reporting Serious Problems to FDA.
Be sure to consult with your doctor before starting a dietary supplement. Supplements may not be safe for certain health conditions, including pregnancy or chronic diseases. They could also lead to harmful side effects if combined with other supplements or medicines, or if consumed in large amounts. Read more on the FDA’s What You Need to Know about Dietary Supplements webpage.
Do I need a vitamin or mineral supplement?
The Dietary Guidelines for Americans recommends that nutrient needs be met mostly from eating a variety of foods and beverages. However, vitamin or mineral supplements may be useful when it is not possible to otherwise meet your nutrient needs, such as during pregnancy or with certain medical conditions. Visit the Vitamin and Mineral Supplements page on Nutrition.gov for general information on the vitamins and minerals that the body needs.
Always talk with your doctor before taking a vitamin or mineral supplement, including multivitamins. Your doctor can review your personal health status and inform you if a supplement could be helpful.
What supplements can help with weight loss?
There is no proof that dietary supplements for weight loss are effective. As with other dietary supplements, weight loss supplements do not need to be tested for safety or effectiveness before they are sold. View these resources for more information on dietary supplements for weight loss:
- Beware of Products Promising Miracle Weight Loss (Food and Drug Administration)
- Dietary Supplements for Weight Loss (Office of Dietary Supplements)
- Herbal Remedies and Supplements for Weight Loss (MedlinePlus)
Lifestyle changes, including a healthy diet and regular exercise, can be a sustainable approach for weight loss. General resources for healthy weight loss can be found on Nutrition.gov’s Strategies for Success page. Work with your doctor or a registered dietitian to find a plan that is right for you.
Diet and Health Conditions
Is there a high blood pressure diet?
Nutrition.gov’s High Blood Pressure page provides nutrition tips for managing high blood pressure, also known as hypertension. You can also read more about salt, how it affects the body, and how to eat less on the Salt and Sodium page. Find other information on topics including the DASH diet (Dietary Approaches to Stop Hypertension) from these sources:
What foods cause gas and bloating?
There are many possible causes of gas and bloating, including:
- Swallowing more air than usual (e.g. when chewing gum or drinking carbonated [fizzy] drinks)
- Eating certain foods or drinks (e.g. “sugar-free” products made with sugar alcohols)
- Having certain digestive disorders (e.g. Celiac Disease, gastritis, Irritable Bowel Syndrome [IBS], or food allergies and intolerances)
Causes of digestive discomfort vary from person to person. If you are concerned, talk to your doctor. They can help you find out why you are having symptoms and how you can make them better.
For more information, read Symptoms & Causes of Gas in the Digestive Tract from the National Institute of Diabetes and Digestive and Kidney Diseases.
What are the most common foods that people are allergic to?
The Food and Drug Administration's (FDA) Food Allergies page lists the most common foods to cause allergies as milk, eggs, fish, crab, lobster, shrimp, almonds and other tree nuts, and peanuts (one of the chief foods responsible for severe anaphylaxis).
What is the difference between a food allergy and a food intolerance?
Read about Food Allergy: An Overview (PDF|1.75 MB) from the National Institute of Allergy and Infectious Diseases. Besides discussing the difference, it explains that food allergies can cause very serious reactions and why it is so important for people with true food allergies to have these allergies identified by a doctor.
How can I get nutrition advice about a medical condition?
- Talk with your doctor or other health professional about referring you to a registered dietitian nutritionist (RDN). An RDN can provide personalized dietary advice taking into consideration your health status (such as other medical conditions), lifestyle, and food likes and dislikes.
- The Academy of Nutrition and Dietetics has a Find a Nutrition Expert online tool that allows you to locate an RDN in your geographical area with particular specialties (such as weight control, diabetes, digestive disorders, etc.). Be advised that this list may not include all RDNs in your area.
- Check with your local health department, hospitals, clinics, and Cooperative Extension for classes such as those on weight management, diabetes, etc.
- For background information, you may find it helpful to look on the Web. Information obtained online, however, does not take the place of personalized advice from a qualified health professional, and some websites have inaccurate or misleading information. In looking for reliable information on the Web, you may want check out our Diet and Health Conditions section.
What foods can I eat to manage my diabetes or pre-diabetes?
Learn about nutrition for diabetes or pre-diabetes with resources from Nutrition.gov's Diabetes page. Other helpful resources that provide tips on meal planning, carb counting, and healthy lifestyle changes include:
- Living with Diabetes: Eat Well (Centers for Disease Control and Prevention)
- Prediabetes - Your Chance to Prevent Type 2 Diabetes (Centers for Disease Control and Prevention)
- Diabetes Diet, Eating, & Physical Activity (National Institute of Diabetes and Digestive and Kidney Diseases)
Consult with your doctor or a registered dietitian when making any changes to your diabetes care plan, including diet changes.
I keep hearing about added sugars. Where can I find more information?
For information about added sugars, including examples of what ingredients to look out for on the food package, read Limit Added Sugars from MyPlate.gov. For tips on reducing your intake of added sugars, check out Cut Back on Added Sugars, based on the 2020-2025 Dietary Guidelines for Americans.
In addition, on May 20, 2016, the Food and Drug Administration (FDA) announced the new Nutrition Facts label for packaged foods. The final rule requires “Includes X g Added Sugars” to be included under “Total Sugars” to help consumers understand how much sugar has been added to the product. For more information, check out Changes to the Nutrition Facts Label.
I heard that MyPyramid has been replaced. Is that true?
Yes. The MyPlate food guidance system replaced MyPyramid in 2011. MyPlate focuses on portion control and using the food groups to create a balanced diet.
What is a "healthy diet"?
A healthy eating pattern is one that provides enough of each essential nutrient from nutrient-dense foods, contains a variety of foods from all of the basic food groups, and focuses on balancing calories consumed with calories expended to help you achieve and sustain a healthy weight. This eating pattern limits intake of solid fats, sugar, salt (sodium) and alcohol. The Dietary Guidelines for Americans consumer pamphlet, Start Simple with MyPlate, provides guidance for creating a healthy eating pattern to reduce the risk of chronic diseases such as diabetes, cancer, and osteoporosis. Additional information on the Dietary Guidelines for Americans is available at https://www.dietaryguidelines.gov/.
How can I find the newest Dietary Guidelines for Americans?
The 2020-2025 Dietary Guidelines for Americans serves as the current dietary guidance through 2025. You can find a copy of the Dietary Guidelines for Americans here.
I would like to get advice about my eating habits. Who should I talk to?
Registered Dietitian Nutritionists (RDN) are health professionals who are trained to provide counseling on nutrition and eating habits. An RDN can provide personalized dietary advice taking into consideration your health status, lifestyle, and food likes and dislikes. The Academy of Nutrition and Dietetics has a Find a Nutrition Expert online search tool that allows you to locate an RDN in your geographical area. Be advised that this list may not include all RDNs in your area.
How many servings from each food group do I need each day?
The number of servings you need each day from each food group depends on your calorie needs. To determine your calorie needs and find the number of servings that is right for you, please visit the MyPlate Plan.
What are RDAs and DRIs?
From 1941 to 1989, the Institute of Medicine's Food and Nutrition Board (FNB) released the Recommended Dietary Allowances or RDAs. The RDAs are a single set of nutrient specific values. During deliberations in the mid-1990's, the FNB decided to replace this single set of values with multiple sets of values, including: Estimated Average Requirements (EAR), Recommended Dietary Allowances (RDA), Adequate Intakes (AI), and Tolerable Upper Intake Levels (UL) for designated age groups, physiologic states (for example, pregnancy), and by sex. These values are collectively referred to as the Dietary Reference Intakes, or DRIs.
Visit the Food and Nutrition Information Center to access the full DRI reports here.
How much of a nutrient is too much?
The Food and Nutrition Board (FNB) defines the Tolerable Upper Intake Level (UL) as the highest level of daily nutrient intake that is likely to pose no risk of adverse health effects to almost all individuals in the general population. This level is different for each nutrient. To view the UL for Vitamins and Elements (also referred to as minerals or electrolytes), please refer to the Tolerable Upper Intake Levels table from the Food and Nutrition Board (FNB).
I've heard that people should cut back on how much trans fat they eat but I'm confused about what trans fats are and what foods have them.
Check out the following resource from the Food and Drug Administration (FDA) that discusses trans fats and how to identify which foods contain them:
I know there are different types of fiber in foods and that they have different effects on the body. Can you tell me about them? How much fiber should I eat?
Yes, the fiber in foods is generally broken down into two broad types - soluble (also called "viscous") and insoluble. Both types have important health effects. According to the DRIs, the recommended intake for total fiber for adults up to 50 years of age is 25 grams per day for women and 38 grams for men. For those over 50, the recommended intake is 21 grams for women and 30 grams for men. See the DRI Macronutrient table.
To learn more about the types of fiber, their functions in the body, and food sources, check out Dietary Fiber from MedlinePlus.
How is food digested?
Digestion begins in the mouth, when we chew and swallow, and is completed in the small intestine. Digestion involves the mixing of food, its movement through the digestive tract, and the breakdown of food into smaller molecules. The digestive process varies for different kinds of food. The National Digestive Diseases Information Clearinghouse website, Your Digestive System and How It Works, explains how food is digested and why digestion is important. This resource is also available in Spanish.
How do I know if nutrition information I find on the Internet is reliable?
The National Library of Medicine's MedlinePlus Guide to Healthy Web Surfing offers suggestions for evaluating the quality of health information on websites.
The National Library of Medicine's MedlinePlus Evaluating Internet Health Information Tutorial is a 16 minute presentation that also teaches you how to evaluate health information found on the Web.
How can I burn off my stored body fat?
We all need some body fat, but if stored fat is excessive it may increase risk of diet-related diseases such as heart disease, diabetes, and some cancers. This is particularly true if excess fat is in the abdominal area. According to the CDC, a body mass index, or BMI, of 25 or higher is an indication that your weight may be unhealthy. Also, a waist circumference of over 40 inches in men and over 35 inches in women indicates excessive abdominal fat if BMI is 25 or higher. Calculate your BMI and find information on measuring your waist size from CDC.
The best strategy for losing excess weight and stored body fat involves calorie reduction, increased physical activity, and a behavior change plan. See Interested in Losing Weight? from Nutrition.gov to learn more.
How many calories do I need to burn to lose a pound of weight?
You need to burn off 3,500 calories more than you take in to lose 1 pound. This translates into a reduction of 500 calories per day to lose 1 pound in a week, or 1000 calories per day to lose 2 pounds in a week. (1-2 pounds per week is generally considered to be a safe rate of weight loss.) This can be achieved by eating fewer calories or using up more through physical activity. A combination of both is best. See CDC's Finding a Balance website to learn more.
I'm on a diet to lose weight. Do I still need to exercise?
Physical activity is a key component of helping you move toward a healthier weight, as it can help you achieve the appropriate calorie balance. People who exercise regularly may be more likely to keep the weight from coming back after losing weight. Check out the following resources on physical activity:
I would like to gain weight. How can I do this in a healthy manner?
Losing, gaining or staying at the same weight all depend on how many calories you eat and how many calories your body uses over time. If you eat more calories than you use, you will gain weight; conversely, if you eat fewer calories than you use, you will lose weight. The Academy of Nutrition and Dietetics’ Healthy Weight Gain website provides some information and advice on how to gain weight and remain healthy.
Because many Americans are overweight, there are many resources geared toward losing weight. Some of these resources explain the principles of weight balance and can provide guidance for you to gain weight in a healthy manner; you will just need to focus on portion sizes for weight gain, rather than weight loss. One such resource is Aim for a Healthy Weight from the National Institute of Health’s National Heart Lung and Blood Institute. There are many other weight control resources on the Healthy Living and Weight section of Nutrition.gov.
If you would like personalized advice, or you want to know how many calories or what types of foods are best for you, Registered Dietitians (RD) are health professionals who can physically assess you and your needs. In the United States, the Academy of Nutrition and Dietetics has a referral service to registered dietitians. You can find a dietitian in your area by using the Find a Nutrition Expert online tool on their website.
I am a 42 year old female weighing 200 pounds and I am 5’5”. Can you provide a diet that will help me lose weight?
We are unable to provide nutrition counseling or create a personalized weight loss plan, however we can point you towards some interactive tools and information that may be helpful. Nutrition.gov’s Strategies for Success website contains a variety of credible weight management resources. In addition, the Body Weight Planner, from the National Institutes of Diabetes and Digestive and Kidney Diseases (NIDDK), allows users to make personalized calorie and physical activity plans to reach a goal weight within a specific time period and to maintain it afterwards.
If you would like a more specific meal plan and want to speak with a nutrition professional, ask your doctor to refer you to a registered dietitian nutritionist (RDN). The Academy of Nutrition and Dietetics also has a Find a Nutrition Expert online tool that allows you to locate an RDN in your area.
How can I get enough nutrients without consuming too many calories?
The Dietary Guidelines for Americans encourages you to choose a variety of nutrient-dense foods and beverages to help achieve recommended nutrient intakes. Foods like vegetables, fruits, whole grains, low-fat dairy products, and lean protein foods can help you get the nutrients you need without excess calories. Avoid excess calories by limiting consumption of foods high in added sugars and solid fats, and alcoholic beverages; these provide calories but are poor sources of essential nutrients. See USDA's MyPlate.gov to learn more about choosing nutrient-dense foods. And, because calorie intake must be balanced with physical activity to control weight, stay active. See the NIH Weight-Control Information Network's Tips to Help You Get Active.
When I eat more than I need what happens to the extra calories?
Consuming extra calories results in an accumulation of stored body fat and weight gain. This is true whether the excess calories come from protein, fat, carbohydrate, or alcohol. See CDC's Finding a Balance website to learn more about the calorie balance equation.
Shopping, Cooking and Food Safety
Does USDA have recipes for people on a budget?
How can I avoid foodborne illness and food poisoning?
The four most important points to remember are: 1. Wash your hands frequently 2. Cook to proper temperatures 3. Refrigerate foods promptly 4. Avoid cross contamination. For more food safety information:
FoodSafety.gov, Gateway to Government Food Safety Information
How long should I keep leftover food?
According to Foodsafety.gov, when refrigerated, most cooked leftovers can be kept for 3 to 4 days, and should be reheated to 165 degrees before consuming. Check out Storage Times for the Refrigerator and Freezer for more information on safe food storage. For other food safety resources, visit Nutrition.gov's Food Storage and Preservation page. You can also submit your food safety related questions to Ask Karen, part of the USDA Food Safety and Inspection Service.
Where can I get information on food labeling?
USDA's Food Safety and Inspection Service (FSIS) regulates the labeling of meat and poultry. The Food and Drug Administration (FDA) is responsible for all other foods. Information on labeling is available from FDA's Food Labeling & Nutrition website. Or check out the FDA's Nutrition Education Resources and Materials website.
Where can I find healthy recipes for different cultures and traditions?
Nutrition.gov collects recipes for a variety of cultures including Native American, Latino, and African American on the Culture and Food page.
I've just moved to a new area and would like to find out if there is a farmers market nearby.
USDA's National Farmers Market Directory can help.
Years ago I received information from USDA on canning fruits and vegetables and would like to know how to get updated information.
The extensive USDA Complete Guide to Home Canning is online. It contains detailed information on canning fruits, vegetables, poultry, red meats, and seafood.
What's In Food
Where can I get information on the level of calories, fat, protein, vitamins and minerals in various foods?
The USDA's Food Data Central has 5 online searchable databases of nutrient composition, which can be used to search for nutrients in common foods. FNIC's Nutrient Lists from Standard Reference Legacy (2018) provide lists of which foods have the most and least content of specific nutrients.
For additional resources, see our What's in Food section.
What is the difference between calories and kilocalories?
The "calorie" we refer to in food is actually kilocalorie. One (1) kilocalorie is the same as one (1) Calorie (upper case C). A kilocalorie is the amount of heat required to raise the temperature of 1 kilogram of water one degree Celsius. Please visit USDA's Food Composition Laboratory for additional information.
I cannot find the food I am looking for in the USDA's FoodData Central. Are there any other places I can look to find the nutrient content of foods?
If you cannot find a food item, or are searching for a food that is not common in the U.S., there are several International Food Composition Resources available where you may be able to find nutrient information on the food you are looking for.
Where can I find a chart or list of foods with calcium?
Find the calcium content in common foods by using the USDA's FoodData Central. You can create a list, sorted either alphabetically by food description or in descending order by calcium content in common household measures. You can also find a list of common foods that have the most and least amounts of calcium in the Nutrient Lists from Standard Reference Legacy (2018) on the FNIC website.
Is the USDA added sugars report still available?
The USDA Food Composition Laboratory has removed the added sugars report from their website. This is due to constant changes in formulations for commercial foods, the primary contributor of added sugars to the diet. No research method can measure added sugars alone, so their amounts must be estimated or supplied by food companies, many of which are not willing to make public such proprietary information. The Agricultural Research Service provides additional information about this decision.
Is there a law that requires food labels to list ingredients that commonly cause food allergies?
The Food Allergen Labeling and Consumer Protection Act of 2004, which went into effect January, 2006, requires that food labels identify in plain English if the product contains any of the eight major food allergens - milk, eggs, fish, crustacean shellfish, peanuts, tree nuts, wheat and soybeans.