Return to Homepage

Don't understand this weight gain

by Grasshopper
(Springfield, TN, USA)

I have been running for 2 weeks and doing some light lifting, but I am gaining weight istead of losing it. What is going on?

Note from Dr. Dan

This sounds like a simple question. Why would someone increase their exercise and then gain weight? It doesn't seem to make sense.

But as this question shows, weight loss and weight gain is not as simple as some would lead you to believe.

Dramatic, sudden shifts in weight are almost always due to water weight. A gallon of water weighs almost 8 pounds. A liter of water weighs a kilogram. That is a lot of weight.

So if you do something that changes the fluid balances in your body you can change your body weight very quickly. Exercising -- particularly if you exercise in the heat -- can make dramatic changes in your weight.

Now, if you exercise and sweat you will lose weight. But sweating stimulates thirst. And therefore you are not likely to lose water over the long term by exercise. You might lose a little by the end of a workout. But you will be thirsty and you'll replace the fluids you lost.

In fact, you are more likely to gain water weight after a workout. First, you may have been mildly dehydrated to start out. Many people are chronically dehydrated, especially overweight people. But the stimulus of the exercise and sweating will cause you to take in more liquids.

This can become a problem, particularly for prolonged periods of exercise. Marathon runners, for instance, tend to be heavier at the end of a race. This is from drinking excess fluid during a race. And if the fluid they drink is water they can develop low sodium levels in the blood -- called hyponatremia -- which can lead to seizures and even death.

So if you are gaining weight after recently exercising, then you might be retaining fluid. That is nothing for you to worry about. It will stabilize.

The next possibility is that you are heavier because you gained muscle mass. If you are doing heavy lifting this is a possibility. But it's hard to gain a lot of mass in only two weeks, so this shouldn't account for a significant amount of weight gain.

And then there is the possibility of increased calorie intake, leading to increased body fat. That is possible too, particularly if weight training is making you hungry, as it does for some people.

To sort it all out you need to do a couple of things. You need to track your weight over a longer period of time, so you can see what the trend is.

You should have some records of what you are eating, in order to see if increased calorie intake is causing you to gain weight.

And of course you should keep exercising. It will make you happier and healthier and you will look better and live longer at whatever weight you are at.

For a lot more information about weight loss take a look at these healthy weight loss tips.

Good luck on your fitness efforts.

Dr. Dan

Click here to post comments

Return to Do you have a weight loss question?.

Where to start:

There is a lot of information on this site. The links below will get you off to a good start.

Most popular pages:

These are some of our most popular pages. They are also some of the most helpful if you are finally ready to lose weight.

You can always reach us:

  • 28960 US Highway 19 North, Suite 115
  • Clearwater, FL 33761
  • (727) 771-8282

  • Or to use our contact form click here.

top of the page