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Publication #FCS8569

Healthy Eating: Fluids1

Linda B. Bobroff2

Why Is Water So Important?

More than one-half of an adult’s body weight is water. Water brings nutrients to the cells in our bodies and removes waste. Our bodies cannot function if they do not receive enough water.

Water helps to:

  • convert food into energy;

  • regulate our body temperature;

  • protect and cushion our vital organs; and

  • keep us "regular."

What Happens If We Do Not Get Enough Water?

When we take in less water than we lose, we become dehydrated. We lose water in urine, sweat, and feces. We replenish our bodies’ water supply by drinking water and other fluids. Foods, especially fruits and vegetables, also provide our bodies with water.

Low fluid intake or dehydration can cause:

  • difficulty swallowing;

  • dry mouth due to low saliva production;

  • headaches;

  • fatigue;

  • loss of appetite;

  • dry eyes;

  • muscle cramps; and/or

  • kidney stones.

Why Is Fluid Intake a Concern for Older Persons?

Mild dehydration is fairly common among healthy persons 65 years of age or older. Those who live in nursing homes are at higher risk. These factors can cause dehydration in older adults:

  • decreased ability to recognize thirst;

  • self-imposed fluid restriction; and/or

  • decreased ability to concentrate urine.

We need to drink enough water and other healthy fluids to stay hydrated. Since older people may not realize they are thirsty, they may need to plan their fluid intake.

Figure 1. 

Older adults may not get enough fluids in their diets, so it is important for them to plan their fluid intake throughout the day.



[Click thumbnail to enlarge.]

How Much Fluid Should We Drink?

The daily fluid intake suggested by health authorities in the US is 9 cups for women and 13 cups for men. The amount an individual needs depends on body weight, activity level, and overall health. The air temperature also affects fluid needs.

These factors increase fluid needs:

  • consumption of high-fiber foods or fiber supplements;

  • certain medications, especially diuretics ("water pills");

  • hot weather; and/or

  • vigorous physical activity.

What Kinds of Fluids Are Best?

Focus on fluids that are low in added sugars and sodium. In addition to water and low-fat milk, you can include a few of these drinks every day to get your water needs:

  • fruit juices (100% juice; about 6 fluid ounces a day is enough);

  • low-sodium vegetable juices;

  • coffee and tea; and

  • vegetable or milk-based soups.

How Can I Include More Water in My Diet?

  • Welcome the day with a cup of water.

  • Drink a cup of water about 30 minutes before meals.

  • Drink a full glass of water when you take your medication. This is best for most medications, but check with your pharmacist.

  • Drink 1–2 cups of water, or more if needed, during and after time spent outdoors.

  • Fill a water bottle and carry it with you during the day.

For More Information

Speak with a registered dietitian (RD). You can find an RD in your area through the Academy of Nutrition and Dietetics by calling the organization’s toll-free number 1-800-877-1600 ext. 5000 (available in English or Spanish) or by visiting its website at

Call your county Extension agent. Look for "Cooperative Extension Service" in your telephone book. In Florida, find your county Extension office at the University of Florida IFAS Extension website:

Other Reliable Websites:



La versión en español de este documento es Alimentación saludable: Líquidos (FCS8569-Span). This document is FCS8569, one of a series of the Department of Family, Youth and Community Sciences, UF/IFAS Extension. First published September 1999. Latest revision June 2016. Visit the EDIS website at


Linda B. Bobroff, RD, LD/N, professor, Department of Family, Youth and Community Sciences; UF/IFAS Extension, Gainesville, FL 32611.

The Institute of Food and Agricultural Sciences (IFAS) is an Equal Opportunity Institution authorized to provide research, educational information and other services only to individuals and institutions that function with non-discrimination with respect to race, creed, color, religion, age, disability, sex, sexual orientation, marital status, national origin, political opinions or affiliations. For more information on obtaining other UF/IFAS Extension publications, contact your county's UF/IFAS Extension office.

U.S. Department of Agriculture, UF/IFAS Extension Service, University of Florida, IFAS, Florida A & M University Cooperative Extension Program, and Boards of County Commissioners Cooperating. Nick T. Place, dean for UF/IFAS Extension.