Why have I gained 5 pounds in a week while working out?

Author: Prof. Dee Conroy IV  |  Last update: Sunday, November 30, 2025

Muscle weighs more than body fat If you've only ever done cardio exercise, you may be confused when a strength-training program leads to weight gain. But the reason for it is simple: Weight training builds lean muscle mass, which is denser than body fat.

Why am I gaining weight so fast while working out?

Muscle is denser (meaning a lot less fluffy) than fat, says Dr. Calabrese. Put another way, 10 pounds of muscle takes up a lot less space than 10 pounds of fat. So, as you start working out regularly and building strength, the new muscle you build may eventually weigh more than the fat you've burnt off.

Why have I gained 5 pounds since working out?

The usual culprit of short-term weight fluctuations is just water retention though. If you have an especially tough workout, your muscles experience microtears. To repair the tears, your body recruits more fluid to aid in the healing process. This can result in a several pound gain on the scale.

Is gaining 5 pounds in a week normal?

Gaining 5 pounds in a week is not typically considered normal or healthy. While short-term fluctuations in weight can occur due to factors like water retention, hormonal changes, or dietary choices, a 5-pound increase in one week is more likely due to excessive calorie intake.

How long does water retention last after exercise?

A single workout's water retention could linger on the scale for 2-3 days or longer. A new ongoing exercise routine can easily stall the scale for 2-3 weeks. If you're sure on your calorie count you will start seeing progress again soon.

How Did I Gain Five Pounds in One Day?

Do you gain weight before losing it?

“Per unit volume, muscle weighs more than fat, so shedding fat and gaining muscle may not immediately change the scale but will result in changes in shape, tone, and measurements,” says McGowan. In other words, you may look leaner as you build muscle and lose fat, but you may actually start to weigh more.

How to flush out water weight?

  1. Exercise Regularly. Daily exercise provides several health benefits, including preventing water retention. ...
  2. Drink More Water. Drinking water to reduce water weight sounds counterintuitive, but it helps. ...
  3. Manage Salt Intake. ...
  4. Cut Carbs. ...
  5. Focus on Certain Foods and Herbs. ...
  6. Try Supplements. ...
  7. Up Your Caffeine Intake.

Why am I gaining weight when I'm eating less and working out?

Key takeaways: Working out can cause short-term weight gain as your muscle mass increases. Post-workout inflammation may cause temporary weight fluctuations. Workout plateaus, supplement use, and dietary changes can also stall your weight-loss efforts.

What is a hormonal belly?

Hormonal belly is when a person gains weight around the abdomen due to hormonal fluctuations. This could be due to changes in thyroid, adrenal, reproductive, or other hormone levels.

Why am I gaining weight when I start exercising?

Introducing any new exercise routine can temporarily stress the body, causing the release of the stress hormone cortisol. High cortisol levels can lead the body to store excess fat, particularly in the abdomen. It can also contribute to inflammation and water retention which will further increase your weight.

Why am I suddenly 5 pounds heavier?

Weight gain and short-term fluctuations may happen for a variety of reasons, such as aging or making lifestyle and dietary changes. However, fast weight gain can be a sign of an underlying health condition, such as a problem with the thyroid, kidneys, or heart.

How long does it take to start losing weight when exercising?

Stage 1: Fast weight loss

In the beginning, weight loss happens pretty rapidly. Over a period of 4-6 weeks, you'll likely see a noticeable difference in your body weight [1] — either on the scales or by the way your clothes fit.

Why did I gain 5 pounds when I started working out?

Gaining weight after working out is likely due to muscle fiber inflammation, muscle glycogen and water weight gain, and over time, muscle mass gain. If weight loss is your goal, seeing an increase on the scale when you've been making an effort to exercise can be frustrating.

How long does it take to see results from working out 5 days a week?

As a rough guide, you'll probably notice some initial changes in the first four to six weeks, but longer-term changes (what you're working toward) will often take around eight to 12 weeks. The good news is that you're likely to start feeling better quickly.

Is my weight gain muscle or fat?

In general, weight gain from fat will result in a softer appearance, while weight gain from muscle will leave you looking leaner and feeling stronger. The most accurate way to assess any change in your body composition is through body composition testing.

Why am I getting fatter while dieting and exercising?

You're eating more

This habit, or similarly rewarding yourself with dessert or a high calorie meal, could be sabotaging your efforts to lose weight. It's easy to overestimate how many calories we burn exercising and if we turn around and consume all of those calories or more, it will likely lead to weight gain.

What is the 30/30/30 rule for weight loss?

The 30/30/30 is a weight loss method that involves eating 30 g of protein within the first 30 minutes of your day and following it with 30 minutes of light exercise. This morning routine is rooted in sound science, and it could be a good way to increase your capacity to burn fat while keeping lean muscle.

How many days a week should I workout?

do at least 150 minutes of moderate intensity activity a week or 75 minutes of vigorous intensity activity a week. spread exercise evenly over 4 to 5 days a week, or every day.

What kills water weight?

Water weight is not usually a cause for concern, but it can be uncomfortable and recurring. Reducing salt and carbohydrate intake, keeping hydrated, and frequently exercising are all good ways to lose water weight and prevent it from returning.

How to lose belly fat fast?

8 Ways to Lose Belly Fat and Live a Healthier Life
  1. Try curbing carbs instead of fats. ...
  2. Think eating plan, not diet. ...
  3. Keep moving. ...
  4. Lift weights. ...
  5. Become a label reader. ...
  6. Move away from processed foods. ...
  7. Focus on the way your clothes fit more than reading a scale. ...
  8. Hang out with health-focused friends.

How do you know if you're losing water weight or fat?

Your Weight Changes Overnight

Similarly, here's another way to determine if it is water weight or fat that you're losing: You gain or lose pounds overnight. If you lost several pounds overnight, that's a good indication that you've shed water weight, according to Texas A&M University.

Which body part loses fat first?

Mostly, losing weight is an internal process. You will first lose hard fat that surrounds your organs like liver, kidneys and then you will start to lose soft fat like waistline and thigh fat. The fat loss from around the organs makes you leaner and stronger.

How to reset body set weight?

After you maintain your new, lower weight for 6 months, you can repeat the cycle and reset your set point again by losing another 10%. Through small, gradual changes in your daily habits, you'll be able to stay at that new, lower weight for the rest of your life.

Why is my body fat increasing with exercise?

As you increase musculature, fat gain can occur due to the caloric surpluses required to increase SMM. This is a well-recognized phenomenon and is commonly referred to in gym-speak as “bulking.”

Previous article
When should you not use salicylic acid?
Next article
How rare is a 315 squat?