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CANCER, WATER and WEIGHT: the importance of hydration through cancer and weight management



Dehydration is a common side effect of cancer treatment and it occurs when your body loses more fluid and electrolytes than it takes in. Our bodies are nearly 60% water, so water is our lifeline.

#Dehydration also can result from exposure to excessive heat, sweating, not consuming enough fluids, medication side effects or the cancer itself.

Why is staying hydrated important for cancer patients?

Water is our nutrient transportation system…Fluids carry nutrients to cells, flush bacteria from the bladder and prevent constipation. Water is also necessary for normal body function and for muscle, connective tissue and joints to move correctly.

Staying hydrated makes treatment side effects less severe and lowers your chances of missing or delaying cancer treatments. If you get dehydrated and it is not addressed, you could it could lead to severe complications, such as seizures, swelling of the brain, kidney failure, shock, coma and even death. Since dehydration can stop normal body functions and be quite dangerous, staying hydrated during treatment is important for protecting your organs from long-term damage.

What are the signs of dehydration?

Some of the signs that you might be dehydrated are:

  • feeling thirsty

  • experiencing dry mouth, lips, gums, and nostrils

  • increased headaches

  • dizziness

  • confusion

  • sleepiness

  • decreased energy

  • muscle cramps

  • darker urine color

  • decreased urination

  • decreased skin elasticity

  • low blood pressure

  • increased body temperature

How do you know if you’re drinking enough water?


Each of us has different fluid needs as our bodies change. For cancer patients, fluid needs depend on many factors, such as the type of cancer treatment you’re undergoing, and whether you are dealing with a fever, diarrhea, vomiting or other gastrointestinal side effects, but a general recommendation is to drink half of your bodyweight in ounces. (I.e. if you weigh 150lbs, a recommended water goal is 75oz)

Another way to make sure you’re hydrated is the urine test — if your pee is clear, you’re doing well… the darker yellow / brown it is, the more dehydrated you are! There are exceptions to this because certain medications and vitamins may cause color changes in your urine. For example, some multivitamins cause it to be bright yellow, some chemo meds like AC (aka red devil) cause it to be red, etc.

Dehydration and weight gain:

Did you know that being dehydrated can actually cause you to gain weight? Water weight that is.

It seems counterintuitive, but dehydration actually causes your body to hold (retain) more water. When you’re dehydrated, your body responds by holding on to as much fluid as possible. Water retention is your body’s natural response to store water so it can function properly. That means water weight actually increases when you’re dehydrated. In fact, dehydration is one of the main causes of water weight gain.

Hydration and weight loss: