Three Reasons Why You Gain Weight Post Workout

It’s Monday morning and you were an absolute savage over the weekend. You ate perfectly, hit your training program or favorite workout class, got your zzz’s in, and even said no to that second drink. You step on the scale- eagerly waiting for the screen to announce the results of your hard efforts. But suddenly, a dark cloud comes over you when the scale flashes a higher number than before.

Wondering "why am I gaining weight while working out?" Don't panic. "Gaining" a few pounds on the scale can be misleading, especially if you’re doing all the right things. Don’t let it get inside your head! (Trust me, it used to get in mine. When I saw the scale go up after riding over 100 miles on the weekend, I didn’t understand why either.)

Because I’ve been there, I’m here to help. Here are three things you need to know about WHY you can gain weight after workout changes:

1. Water Retention After Exercise

Water can alter your weight by as much as 10 pounds (or more).

Think you just lost a few pounds from that epic bike ride or Barry’s Bootcamp class? Don't get too excited-it's just water loss due to sweat. And if you're seeing a higher number, that could be due to water retention (your body tends to hold onto water when its dehydrated). The takeaway: the amount of water in your system has a heavy influence on the number you see on the scale.

Water makes up approximately 65-90 percent of a person’s weight, and deviation in water content can move the scale by up to ten pounds from day to day. This is one of the main reasons diuretics have become so popular and can now be purchased from a local CVS on the fitness supplement aisle. While they may help you shed a pound or two before that beach trip on 30A, it won’t provide lasting body composition changes.

2. Weight Gain the Day After a Workout

A lot of factors can influence your weight- including your workouts.

Have you ever noticed that right after (or even a day or two after) an intense workout the scale goes up? That's normal, and it doesn’t mean you’ve gained a few pounds of fat or muscle overnight. It’s called recovery.

Your weight on a scale is a combination of muscle, fat, bone, the brain and neural tract, connective tissue, blood, lymph, intestinal gas, urine, and the air that we carry in our lungs. Immediately after a workout routine, the percentage of mass in each of these categories can shift as much as 15 percent. Intense workouts and training weeks cause variability on the scale due to factors like hydration, inflammation from muscle damage repair (also, known as the infamous DOMS- delayed onset muscle soreness…ie, why it’s hard to sit after leg day), and even the amount of intestinal by-product or urine and blood volume.

*Lets out sigh of relief*

If you’ve gained weight from a hard workout (assuming you didn’t pound a 10 oz. burger and a marg immediately after), it’s probably not the type of weight gain that you think it is. So, chill!

3. Weight Gain with Muscle vs. Fat

Muscle does NOT weigh more than fat.

We’ve all heard it. One of the most misleading statements that kills me. “Muscle weighs more than fat.” Well, no. If you passed fifth grade math, you should know that one pound of muscle weighs the same as one pound of fat. They both weigh one pound.

HOWEVER, the volume of muscle is denser than the volume of fat, and therefore heavier if we’re measuring it that way. When you start to add more weight bearing activity to your workouts and build more dense muscle while decreasing your bodyfat, the scale weight may increase. But these changes happen over weeks and months (not hours, days or your first week in the gym) so the scale is useless when tracking them.

The best way to track these types of changes is to use a medical grade bodyfat test (not a 3-caliper test by Steve at the gym or a hand-held device by Tommy at GNC). I use a local Atlanta business, The Dunk Truck, that uses hydrostatic (underwater) weighing methods. Another good option is a DEXA scan (Live Lean Rx).

And there you have it! Hopefully, this helps debunk a few myths and comforts you to know that by weighing more post workout, you aren’t backpedaling and not making progress.