Eat Your Water for Weight Loss


Verywell / Alexandra Shytsman

Losing pounds and maintaining a healthy weight can be tough as you get older. Small increases in calorie intake, combined with less physical activity and hormonal shifts, can add up to weight gain over time, leaving us vulnerable to age-related conditions like cardiovascular disease, diabetes, and fatty liver disease.

While many approaches to weight loss aim to reduce some component of our diet (lowering fat, carbohydrates, or overall glycemic index), a leading nutrition researcher says a very effective approach involves increasing your intake of one of food's most fundamental ingredients: water.

Barbara Rolls, Director of Pennsylvania State University's Laboratory for the Study of Human Ingestive Behavior, says that consuming more water in food, not just alongside your meal as a beverage, can help you feel fuller and more satisfied with fewer calories.

We Choose by Weight, Not Calories

Back in the late 1990s, Rolls and colleagues discovered an intriguing aspect to the way most people consume food day today. Rather than choosing items that offer the same amount of energy (in calories) in their regular meals, the researchers found that most people eat the same weight of food day in and day out. This was established in Rolls's food lab, where subjects' eating choices were weighed before and after test meals.

Such a finding was valuable because it suggested that people trying to lose weight or maintain a healthy weight could "trick" themselves into feeling satisfied with fewer calories, as long as the weight of what they consumed remained constant.

Subsequent studies confirmed this was true. For example, subjects brought into the food lab for weekly lunches were unknowingly offered pasta dishes of differing calorie content. One week they had typical meat and tomato sauce, while the next they had a dish containing 12% to 24% fewer calories, achieved by substituting pureed or chopped vegetables (high in water content, low in calories) for some of the pasta.

Rolls says the subjects typically ate exactly the same portion size, regardless of the shifting calorie content (what her team dubbed "calorie density") without feeling hungry, or eating more later in the day, to compensate.

Why Not Just Drink More Water? 

For some reason, our bodies do not process water consumed as a beverage in the same way it uses water "hidden" in solid food, according to Rolls.

Research shows that people offered soup or a casserole will report feeling fuller and satisfied than subjects offered precisely the same components as separate vegetables, carbohydrates, and other ingredients along with a glass of water.

"It appears that the gastrointestinal tract handles water differently depending on whether you drink it or it's incorporated into a dish," she says. "Water bound into food takes longer to exit the stomach, there's more swallowing, and because the portions can appear large, there are visual cues as well that affect satiety, or satisfaction."

Even better, Rolls points out, looking for the best water-rich foods leads you to the kind of nutrient-dense choices like fruits and vegetables that you should be consuming anyway, as part of a healthy, balanced diet. Besides, she says, adding more produce to your plate will keep your portions large and satisfying.

Best Ways to "Eat Your Water"

You can "eat more to eat less" by trying these meal tricks:

  • Start each meal with a low-calorie salad or soup, both of which have been proven to reduce the number of calories consumed later in the meal.
  • Swap non-starchy vegetables for some grains in your favorite dish or recipe.
  • Limit meats and grains so they each occupy no more than a quarter of your plate (meats should occupy a quarter and grains will occupy another quarter of your plate).
  • Aim to fill half your plate with vegetables prepared in a way that keeps their calorie content low (steaming, sauteeing, or microwaving).
  • Try adding a second or third vegetable portion for greater variety, rather than increasing the amount of a single vegetable.
  • Try a small portion of healthy food, like high water fruits (melons or berries) at the end of a meal in place of a dessert.

Another smart tip is to choose foods that are naturally higher in water. You'll find many fruits and vegetables are great choices, including:

  • Apples
  • Blueberries
  • Broccoli
  • Bananas
  • Cabbage
  • Cantaloupe
  • Carrots
  • Cauliflower
  • Celery
  • Cucumbers
  • Grapefruit
  • Grapes
  • Jicama
  • Kiwi
  • Lettuce
  • Oranges
  • Peaches
  • Pears
  • Peppers (sweet)
  • Pineapple
  • Radishes
  • Spinach
  • Strawberries
  • Tomatoes
  • Watermelon
  • Zucchini

Shouldn't You Reduce Portion Size for Weight Loss? 

Portions served in restaurants, homes, and even those recommended in many cookbooks may be more food than you need to feel satiated. Remember to practice mindful eating at meal time and when snacking. Eat slowly and enjoy your food until you feel satisfied, then stop (even if there is food left on your plate).

Rolls says that if most of your foods are of the calorie-dense variety, containing high levels of added fats and sugars, you'll put on weight. Still, she maintains that overall calorie content, not serving size, is what determines whether people gain, lose, or maintain their body weight.

"The trouble is," she observes, "that people have a really hard time reducing portion sizes. Their expectation of how much food to eat is based on thousands of previous eating experiences. If it's less food than they expect, they assume even before eating anything that they'll remain hungry afterward."

Indeed, Rolls says that telling people to eat less has not been a successful strategy for the population at large. Providing generous portions is an easier sell, she insists, and these portions can still be healthy if they contain fewer calories. In her book, "The Ultimate Volumetrics Diet," she advises boosting the water content of meals to create large, satisfying portions with a lower calorie density.

2 Sources
Verywell Fit uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Barbara Rolls, Nutrition Professor. Pennsylvania State University. Interview conducted April 30, 2013.

  2. Rolls B, Hermann M. The Ultimate Volumetrics Diet. New York: Harper Collins; 2012.

Additional Reading

By Sharon Basaraba
Sharon Basaraba is an award-winning reporter and senior scientific communications advisor for Alberta Health Services in Alberta, Canada.