How Much Water You Should Drink and Other Minimum Standards for Health

An Army staff sergeant drinks from a 16-ounce bottle of water.
Staff Sgt. Shaun Martin, a combat medic assigned to Blanchfield’s LaPointe Army Medical Home on Fort Campbell, drinks from a 16-ounce bottle of water to maintain his hydration for optimal performance. (Maria Yager/U.S. Army photo)

If you have read my articles and books in the past, you will see a common thread in all of my writings: Surpass the minimum standards in physical fitness testing if your profession (or life) is physically demanding. This mantra holds water with military, law enforcement, firefighting and other public servants whose daily job requirements have physical challenges that may mean life or death.

I often get asked, "How much of this or that should I do or eat?" Here are a few of those answers, according to many health professionals around the country. No matter if we are active or not, we should strive to hit at least the minimum standards in areas below:

The standards below are gathered through research of a variety of sources, including the Food and Drug Administration, the National Academies newsletter and Harvard School of Medicine.

Daily water intake

The minimum standards for daily water intake are universally recognized and set at 2.5-3 liters per day (or approximately 85-101 fluid ounces). Personally, I like to push that a little higher if you are physically active and sweat during your average day. I round it up to a minimum of a gallon a day.

Exercise sessions

The minimum standard for weekly exercise sessions per week is four that last at least 30-45 minutes. This standard is a minimum requirement to decrease the chances of having diabetes as you age.

Daily fruits and vegetables

The minimum daily recommended standard for fruits and vegetables consumed is five servings. If active, I recommend five servings each of fruits and vegetables.

Body mass index

Maintain a BMI of less than 25. To determine BMI:

BMI = 

        Weight in pounds/             

(height in inches) x (height in inches)

x 703

This standard of measure is fairly controversial as it does not take into account a low body fat and above-average muscle mass. So a 200-pound man who is less than six feet tall with less than 7% body fat is considered overweight.

Minimum protein amount per day

The standard method used by nutritionists to estimate our minimum daily protein requirement in grams is to multiply the body weight in kilograms by .8. (Convert pounds to kilograms by dividing your body weight in pounds by 2.2.) So using this formula, a 200-pound person should get 73 grams of protein a day. 

It has been recommended that endurance athletes, weightlifters and highly active people get more protein grams per day to assist with the repairing of muscle tissue and increasing caloric intake to help maintain weight. Some estimates have been in the range of multiplying body weight in kilograms by 1.4 to 1.7 for daily protein recommendations, thus increasing the range from 127 grams to 155 grams protein per day.

You should see a nutritionist if you decide to go higher than the recommended amounts, as high protein amounts can leach calcium from bones and challenge the kidneys to work overtime. Add more water to your diet as you add more protein, too.

Daily carbohydrates

There are many variables for carbohydrate intake, depending on physical activity level and dietary goals:

Weight-loss goals and performing low-intensity exercise:

100 grams per day

Weight training:

100 grams per day or 2.5 grams/set of exercise done

Moderate, longer duration activity:

2-2.5 grams/pounds of body weight of carbohydrates per day

High-intensity/endurance sports:

3-4 grams/pounds of body weight of carbohydrates per day

Daily fat grams

Calories from fat should not exceed 30% of your total daily caloric consumption. Calories from saturated fat should not exceed 10%. For optimal health, you should try to avoid as much saturated fat as possible by trimming fat off meat and avoiding whole milk, butter, etc.

Salt intake

Healthy 19- to 50-year-old adults should consume 1.5 grams (1,500 milligrams) of sodium and 2.3 grams of chloride each day -- or 3.8 grams of salt -- to replace the amount lost daily on average through perspiration and to achieve a diet that provides sufficient amounts of other essential nutrients. Canned vegetables, soups and sodas are Americans' biggest contributor to sodium in our diets.

Striving for the minimums is not a bad thing if you are nowhere near the daily recommended amounts of water or nutrient intake or exercise sessions. These were several of the questions that readers have emailed me in the past, so it is not a total and comprehensive study of what you need to do and eat to stay healthy.

Stew Smith is a former Navy SEAL and fitness author certified as a Strength and Conditioning Specialist (CSCS) with the National Strength and Conditioning Association. Visit his Fitness eBook store if you're looking to start a workout program to create a healthy lifestyle. Send your fitness questions to

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