Nov 18, 20234 min read

Are you gaining weight from working out?

Most people who start working out expect to experience certain things after the first few workouts: muscle soreness, stiffness in our joints, and fatigue. One thing we usually hope to see is weight loss.

However, some people who begin a new exercise routine step on the scale after their first few workouts and are shocked to find that instead of seeing the number going down, they appear to be gaining weight after working out.

After running into a new member and chatting with her about SFV, she asked a very important question with a bit of panic in her voice—“Why am I gaining weight after working out?”

#1: Post-Workout Muscle Inflammation

The most common cause for gaining weight after working out, particularly during the first few weeks of a new training program or after a particularly intense workout, is due to water retention.

This is temporary weight gain rather than a true increase in body fat. Whenever you perform some type of stressful exercise such as running, intense strength training, or an interval workout, there is some amount of structural muscle damage that occurs.

Overloading your muscles causes micro-tears in the muscle fibers. This initiates a reparative process that will ultimately rebuild and strengthen your muscles. However, it also triggers a cascade of inflammation.

The body retains excess water to help facilitate the muscle reparative process.

Before you panic, the important question becomes, “How long does temporary weight gain after exercise last?”

In most cases, unless you caused pretty severe damage to your muscles, with proper fueling, hydration, and recovery, any temporary weight gain after working out from water retention should subside in about 72 hours.

#2: Your Diet Is High In Carbohydrates

Another common cause for gaining weight after working out is also due to water retention, but rather than the body holding onto water because of muscle damage and inflammation, the body is storing more water due to your diet.

You NEED carbohydrates after a hard workout. Carbohydrates supply the glycogen your muscles need when producing energy during high-intensity exercise. SFV is a strength training program that requires endurance exercises and that requires you to fuel with carbohydrates after workouts to support energy production.

For every gram of carbohydrates that your body stores as glycogen, another 3-4 grams of water are also stored because glycogen has to bind with water in order to be metabolized by the muscles for energy.

#3: You Are Increasing Your Muscle Mass

Depending on the type of training that you are doing and the diet that you are following, you might be gaining weight despite exercising because you are building muscle.

If you are engaging in hypertrophy training or intense strength training workouts and consume an adequate number of calories and grams of protein per day to support muscle growth, your body will respond favorably to your workouts by increasing your lean muscle mass.

It is possible to lose fat and gain muscle at the same time, which would result in no net weight gain or weight loss. This is often tricky to do on your own and requires discipline in your diet and training program. We tackle this every year in the Hot Girl Summer Challenge.

Muscle does not weigh more than fat. One pound of muscle and one pound of fat weigh the exact same: one pound. However, the volume taken up by one pound of muscle and one pound of fat is different.

Muscle tissue is denser than fat, so if you gain muscle and lose fat at the exact same rate, your overall body size (or the size of clothes you wear) will go down. Your circumference measurements will drop, and you’ll look leaner, but your weight on the scale will remain unchanged.

#4: You Aren’t drinking enough water

Probably the most counterintuitive but common reason that you may be gaining weight after exercise is dehydration.

When you exercise, your body sweats, and you also lose more water through increased exhalation, which increases the amount of expired respiratory water vapor.

Therefore, unless you are taking in enough fluids before, during, and after your workout, you can easily become dehydrated, especially during longer endurance workouts or when exercising in a warm environment.

On the one hand, when you are dehydrated, your total body water levels drop, which would result in a decrease in your weight on the scale.

However, dehydration actually causes the body to retain more water, as water is viewed as a scarce resource.

Although immediately after a very sweaty workout, it will appear that you have lost weight if you do not rehydrate the following day, you may find that you have gained weight on the scale because your body is now holding onto more water.

#5: You Are Overeating

Although working out does burn calories, some people overestimate the number of calories they have burned, which leads to over eating excess calories.

You want to get out of the habit of “rewarding yourself“ with food after a workout. Compensatory overeating can negate the caloric deficit you generated by doing the exercise in the first place and lead to a net caloric surplus. This will result in true weight gain because you are consuming more calories than you are burning.

#6: You Are Overtraining

If you’re doing a lot of exercise, it’s natural to assume that you’d lose weight or at least not be gaining weight. However, overtraining or doing too much exercise can over-stress the body. Overtraining and physically taxing workouts can increase your levels of cortisol, which is the primary stress hormone. High levels of cortisol have been associated with increased appetite and an increased risk of weight gain, particularly in the abdominal area. It's possible that if you’re not allowing your body enough time to recover and you’re red-lining your efforts day after day, you’re gaining weight because your hormones are imbalanced and your cortisol levels are too high.

#7: You Just Started Working Out

Beginners who have just started a workout program are most apt to gain weight after working out. As mentioned, the body retains water to help the muscles repair damage after exercise, and if your body is unaccustomed to working out, there’s a greater chance that any type of physical activity will cause some amount of damage. Your body retains fluid to help bring healing nutrients to the site of any structural damage to heal your muscles. Stay consistent with your diet, water intake, and rest days.