Have you ever wondered why your weight can vary so drastically from day to day?   Have you ever noticed how the scale drops fairly rapidly when you begin a weight loss program and then a few weeks into the program your numbers begin to move down more slowly?  At this point you can become discouraged and even decide to give up all of your efforts.  You may get caught up with numbers on a scale and either don’t realize or overlook the fact that you are predominantly losing water weight.   Changes in water balance can vary considerably from one day to the next.  So how does this happen?

The human body is about 60% water and water is lost from the body by breathing, sweating and urination.  All water losses are replaced by drinking and eating.  How you balance the water coming in, to the water leaving our body differs from one individual to the next.

There are a few things to take into consideration regarding water balance in your body.  What causes your body to gain water weight?

Sodium is present in salt and causes you to retain water.  You can gain up to 5 pounds overnight because of excess sodium.  If you have ever eaten a meal high in salt the night before weighing the following morning – you know what I’m talking about.

When you eat complex carbohydrates your muscles stores it as glycogen and this retains three times its weight in water.  That is why your scale reads higher the day after you have consumed more carbohydrates than usual.

There are also a few supplements such Creatine that can cause you to gain water weight.

Some medications and hormones will also increase your water retention resulting in a higher number on your scale.

Water weight is lost fairly rapidly by: 

  • Decreasing your intake of sodium and/or carbohydrates.  This can be done by simply reducing your overall food intake because you will automatically consume less sodium and carbohydrate by eating less.
  • All food contains some water and eating less means consuming less fluid. Taking in less fluid than your body uses will show weight loss on the scale, however, it can be dangerous if fluid is not replaced adequately.  Drinking water also helps to prevent water retention.
  • If you break down muscle protein as you lose weight, you will also show water loss since the protein in your muscle holds up to 4 times its weight in fluid.  You really don’t want to lose muscle as you lose weight because you will diminish our ability to burn calories.
  • Water depletion through activity and/or by being out in the heat will also cause water loss and a lower number on the scale – but it is not safe.  Wearing sweat suits in the gym also causes dehydration and not fat loss as so many people assume.

The bottom line is that when you begin a weight loss program your fluid balance is altered and you may see an immediate poundage loss on the scale that will slow down as your body adjusts.  With approximately 3,500 calories in one pound of fat, you would have to cut back 500 calories a day to lose one pound of fat in a week.  All the extra weight lost in water will return as fast as it disappeared!  Checking your body fat measurements is a much more accurate way of establishing real fat loss.  No fast weight loss could ever be fat loss because fat cannot be burned that quickly. 

Ife Ojugbeli, MD, MBA.