Fast Facts:

Read these if you just want the basic recommendation.

1) The general consensus among health authorities is 8-eight ounce glasses of water should be consumed per day (not including water consumed from other sources).

2) Consuming water frequently (like with meals and snacks) has been shown to reduce calorie consumption and increase fullness. This reduction in calorie intake can lead to fat loss.

3) Increasing water consumption is a simple (and free) dietary habit that can boost confidence and help cement healthy lifestyle change.

4) Since the goal of adequate hydration is to balance water being lost through sweat, urine, and feces with water ingested, all water contributes. That is the water found in sodas, coffee, fruits/vegetables, soups and so on. Keeping that in mind, most people in the industrialized world aren’t significantly dehydrated.

5) More than half of the human body is composed of water. Yet, replenishing water loss is a fairly simple mechanism. Thirst centers in the brain will just tell you when to drink! As long as you listen to those cues, you should stay adequately hydrated. It should be noted, however, that when exercising under thermal stress (high heat AND humidity), our thirst sensors can malfunction. In this case, thirst will not be adequate in order to maintain hydration.

Scientific Support & Evidence:

Read this if you want to know what we base our recommendations on.

1) Thirst and fluid regulation is very tightly controlled by two mechanisms:
-The renin angiotensin system in the kidney’s response to a drop in blood volume (water in the blood stream).
– Osmoreceptors that lie just outside the brain can sense the concentration of blood plasma (the amount of sodium in the blood).

2) When blood volume or concentration drops, these mechanism kick in:
– The renin angiotensin system releases a specialized series of hormones (ending with angiotensin II) that increases water and sodium absorption by the body. Likewise, angiotensin II stimulates the urge to drink and eat salt.
– When the osmoreceptors become activated, they aid in maintaining fluid balance by increasing a hormone known as vasopressin, which also acts on the kidneys to retain fluid.

3) Dehydration typically only occurs during heavy exercise in high heat/humidity OR if a medical issue occurs (like vomiting, diarrhea, or burns/skin diseases. Yellow/amber urine can be a sign of dehydration. Losing as little as 1-2% of your total body water (which could be as little as a pound), can result in performance impairments and illness.

4) Mechanistically, there is no reason that increased water consumption would directly increase weight loss. However, if water is replacing a higher calorie, sugar-filled beverage OR it fills you up, it could certainly indirectly lead to weight loss. Furthermore, research suggest people who drink more water are more aware of their diet, and tend to consume fewer calories (on average 200-300/day less).

Links to Other Informational Resources:

Click below if you’d like more in-depth information.

1) WebMD: The Wonders of Water

2) Mayo Clinic: Water: How much should you drink every day?

3) Peer-Reviewed Journal Article: Association between water consumption and body weight outcomes: a systematic review

4) Peer-Reviewed Journal Article: Effects on weight loss in adults of replacing diet beverages with water during a hypoenergetic diet: a randomized, 24-wk clinical trial