A new exercise regimen puts stress on your muscle fibers. This causes small micro tears, also known as micro trauma, and some inflammation. Those two conditions in your muscle fibers are the reason you may gain some weight.
There are several research-backed reasons why you might notice a slight weight gain after exercise. These include muscle gain, water retention, post-workout inflammation, supplement use, or even undigested food. In most cases, post-workout weight gain is temporary.
Improved Body Composition
Strength training may cause you to gain weight, but that's perfectly okay. If you increase the amount of lean body mass, you will look leaner and toned. Muscle is denser than fat, meaning it takes up less space on your body.
“When you start exercising, your muscles start gobbling up fuel called glycogen,” says Krista Scott-Dixon, Ph. D., Director, Headspace Adjustment Bureau, Precision Nutrition. Since glycogen stores water, you could gain up to 10 pounds in water weight alone, says Scott-Dixon.
You've gained muscle.
So as you gain more muscle and lose fat, you change your overall body composition, which can result in a higher weight, but a smaller figure and better health. If the scale has inched up, but your waistline hasn't and you feel strong overall, don't sweat the pounds; they're increasing your power.
Temporary weight gain after exercise will last anywhere from two days to 14 days. Meaning, give yourself two weeks for that weight to vanish the same way it came.
You're gaining muscle. The scale might be stuck because you're building up your biceps and glutes—and that's a good thing. The number on the scale is less important than the breakdown of how much water, muscle, and fat are in your body, Jovanovic says.
When you gain muscle, you'll notice that your muscles naturally look more defined and are more visible, Berkow said. (To see your abs specifically, you'd have to also lose fat.) Your muscles would also be larger in size or feel "harder." If you gain fat, you'll notice more softness, she said, and you'll gain inches.
Should you weigh yourself after a workout? It is generally not recommended to weigh yourself immediately after a workout, as your weight can fluctuate due to several factors such as hydration level, muscle soreness, and inflammation.
In order to repair itself after exercise, the body sends extra fluid to your tissues. While the process is actually important for recovery, the excess fluid can make you feel heavier than you did before a workout.
Muscle fitness – expect to see small changes in the first few weeks. Within three to six months, an individual can see a 25 to 100% improvement in their muscular fitness – provided a regular resistance program is followed.
Weight lifting may not set you up for the calorie deficit that cardio can, but it may help ensure that your body burns fat instead of muscle. One study found that people who completed two to three 45- to 60-minute strength training sessions lost 1.4% of their total body fat on average after 5 months.
One of the main reasons why burning calories through exercise may still not result in weight loss is due to overexertion, or inflammation of your body. If you exercise too hard on a daily basis, there is an excess of inflammation in your body. All the added up inflammation makes you gain more weight than lose.
Muscle Gain
Another reason you could be gaining weight working out is that you're building muscle faster than you're shedding fat. The general consensus in the fitness community is that the most weight someone new to fitness will gain in muscle is about two pounds a month, but that's not a hard-and-fast number.
In terms of losing weight through exercise, he says people can start seeing results in two to three weeks. But he explains that if you want to keep the weight off, you'll need a routine that progresses slowly and steadily instead of one where you're going all out.
1 kg of muscle may appear to be the size of baseball whilst 1kg of fat will be three times the size and look like a wobbly bowl of Jelly. Muscle is a denser tissue that takes up less room in our bodies than an equal weight of fat.
Muscle mass is denser than fat mass and you will undoubtedly gain weight from lean muscle gains. While your clothes may feel looser, the scale may tell you otherwise. This is a win!
In one one study from the University of Central Missouri, experienced lifters gained an average of 2.18 to 2.33 pounds of muscle over the course of an eight-week training program—not as much as you might expect from a newbie just hitting the gym.
The reason your body feels like it was run over by a truck when you start working out again after a lull is due to stress in your muscle fibers. Exercise causes micro tears and inflammation, two culprits the temporary weight gain. Muscles repair damaged tissues through protein synthesis, which requires water retention.
Intense workout stresses our body in a positive way. That stress and micro-tearing damage to the muscle fibers induces water retention in the body. Your body releases cortisol during exercise, which can impact your fluids and cause your body to retain water.
Glycogen for the Muscles
That means more glycogen and thus more “fuel” in your muscles, adding to their weight. This weight gain could be 1 to 3 pounds, and each pound of muscle holds about 3 pounds of water.
This phenomenon is sometimes called “phantom fat” or “phantom fat syndrome.” The medical term is body dysmorphic disorder, said Giovanni M. Billings, Psy. D., a psychologist who works with surgical weight loss patients. The disorder can involve other aspects of a person's self image, not just weight.