why is this happening to me?!

i am in the same boat as you, i am gaining a little weight as well. However you say you are working our vigorously, so your body is gaining muscle. muscle weighs more than fat, so maybe next week take your measurements and see if you have lost anything their. also make sure you are eating enough because if not then your body is gonna store everything you eat and not burn it off, hence starvation mode. but dont give up, keep going and all your hard work will pay off in no time.

No, it is not muscle, it is water weight in your muscles to repair the micro tears caused from intense exercise. It is next to impossible to gain muscle while in a caloric deficit, and even harder for a woman due to testosterone levels.

Are you ABSOLUTELY certain you're eating at a deficit? I know many of my friends underestimate their caloric intake and overestimate their calories burned and wonder why they aren't losing weight, it's because they are actually at maintenance.

No offense, but you look to be at a healthy weight if not even on the thin side. Perhaps you are at your goal weight? Why do you feel you need to loose?

"Why the Scale Lies

As a personal trainer I’m constantly warning people that the scales are an evil contraption designed to make us feel bad about ourselves and so “diet clubs” can look down on you and say “have you been cheating” to make you feel even worse!

I constantly tell people over and over again that daily weighing is unnecessary, yet how many of you cannot break the ritual of hoping on the scales every day. Do your self a favour and throw the scales in the bin or my favorite, give them to someone you don’t like! If you can’t bring yourself to do either of those then you should definitely familiarize yourself with the factors that can influence its readings. When you factor in things like water retention, glycogen storage and changes in lean body mass, fluctuations in your body weight is normal. The bathroom scale should not be looked upon as your sole guide of success or failure. Once you understand more about how the body works, you can free yourself from the daily battle with the bathroom scale.

Your body is made up of approximately 60% water. Daily fluctuations in the body’s water content can send scale-watchers into a panic if they don’t understand what’s happening. Two things that can influence water retention are water consumption and salt intake. As strange as it may sound, the less water that you drink, the more of it your body retains! If you are even slightly dehydrated your body will hang onto its water supplies, possibly causing the number on the scale to creep upward. So if you are thirsty, drink up as you are already dehydrated!

Excessive amounts of salt (sodium) in our diet can also play a big role in water retention. A single teaspoon of salt contains over 2,000 mg of sodium. As a guide, we should only eating between 1,000 and 3,000 mg of sodium per day, so it can be easy to go overboard. Sodium is a sneaky substance, its in nearly everything you eat and drink. The more highly processed a food is, the more likely it is to have a high sodium content. That is why, when it comes to nutrition I recommend sticking to the basics: fruits, vegetables, lean meat, beans, and whole grains. Be sure to read the labels on canned foods, frozen meals and anything that comes packaged in a box.

Women may also retain several pounds of water prior to menstruation. This is very common and the weight will likely disappear as quickly as it arrives. As with general water retention, pre-menstrual water-weight gain can be minimized by drinking lots of water, maintaining an exercise program, and keeping high-sodium processed foods to a minimum.

The body stores carbohydrates as glycogen. Think of glycogen as the fuel tank for daily living. Some of this glycogen is stored in the liver and some is stored the muscles themselves. This energy reserve weighs more than a pound and for every gram of glycogen stored the body stores approximately 4 grams of water. This can add up to 3-4 pounds of water weight when its stored. Your glycogen supplies, along with the stored water, will shrink during the day if you fail to take in enough carbohydrates. When this happens our weight will drop on the scales but its only temporarily because as soon as we eat a meal containing carbohydrates the body will fill the glycogen fuel tank along with storing water. It’s normal to experience glycogen and water weight fluctuations of up to 2 pounds per day even with no changes in your calorie intake or activity level. These fluctuations have nothing to do with fat loss, however I can imagine they would make the weekly weigh-in at the diet club frustrating, something I’m sure they don’t tell you about!

People also tend to forget the actual weight of the food that we eat on a daily basis will affect the number on the scale. So eating a big meal along with any drinks before hopping on the scale is only going to result in a higher reading. The 5 pounds you put on right after eating a huge meal with drinks is not fat, it’s the weight of the food and will be gone in several hours when the body has finished digesting it. For this reason, it’s a good idea to weigh yourself first thing in the morning before you’ve had anything to eat or drink.

In order to store one pound of fat we need to eat 3500 calories above our daily caloric needs. So if you take the above example, to actually store the above dinner as 5 pounds of fat, you would have to eat a massive 17,500 calories. This is highly unlikely, and in fact it’s probably not humanly possible(but please don’t try to prove me wrong!). So if the scale goes up 3 or 4 pounds overnight, relax, as it’s most likely increased water weight, glycogen, and the weight of your dinner. Bear in mind that the 3,500 calorie rule also works in reverse. If our goal is to lose one pound of fat you will need to burn an extra 3,500 calories more than you take eat. Generally, it’s only possible to lose 1-2 pounds of fat per week. So when you follow a severely low calorie diet that causes your weight to drop 10 pounds in 7 days, it’s physically impossible for all of that to be fat. What you’re really losing is water, glycogen, and muscle.

This brings me to the scale’s sneakiest lie. The scale doesn’t just weigh fat; in fact it only tells you how heavy you are under gravity at that moment. So when you hope on the scale what it collectively weighs your muscles, bones, water, internal organs, in fact everything that is you. Losing weight and losing fat are two different things and in fact, the scale has no way of telling you what you’ve lost (or gained). With that in mind, if you have been on a restrictive diet and lost a lot of weight in a short period of time then you have probably lost a lot of muscle tissue. Losing muscle is nothing to celebrate. Muscle is a metabolically active tissue, the more muscle you have the more calories your body burns on a daily basis, even while you are sat reading this. That’s one of the reasons why a fit, active person is able to eat considerably more food than the dieter who is painfully counting points and who is unwittingly destroying muscle tissue. Also if you are losing a lot of weight by crash dieting and not exercising and therefore by sacrificing muscle tissue you will not get the body transformation results you desire. You will just end up a smaller version of yourself. Or as one of my clients recently put it, a smaller fat person!

If you were to compare your muscles and fat to gold and feathers with one pound of fat being a big lumpy bag of feathers, and one pound of muscle as a small but extremely valuable piece of gold. Our goal would then be to get rid of the lumpy feathers and replace it with as much gold as possible. So in effect we would weigh exactly the same the only problem with the scale is that it doesn’t differentiate between the two. It can’t tell you how much of your total body weight is lean tissue (gold) and how much is fat (feathers).

Skin-fold calipers, hydrostatic (or underwater) weighing and bioelectrical impedance are all methods we can use to measure our body composition to discern whether we are losing (or gaining) fat and muscle and while none of these methods are 100% accurate, they offer a better way of measuring our bodies changes than the scale.

Now if the thought of being pinched, dunked, or gently electrocuted doesn’t appeal to you, don’t worry, one of the best measurement tool of all is a simple tape measure and your very own eyes. If the tape is showing that you have lost inches, your clothes fit better and the person looking back at you in the mirror is a leaner, fitter more confident person who isn’t bound by different coloured days then surly that is a better judge of your success than the lies from the bathroom scale.

Do yourself a favour and buy yourself a big hammer and introduce it to the springy, beady eyed lying menace, not only will you release a lot of built up tension but you will feel better for it, (just be sure to wear the correct safety clothing)!

Train Hard, Eat Smart!

I can tell you from experience that you are more then likely gaining muscle weight. This is normal as muscle weighs more than fat.
try changing up what you do to "shock" your system, occassionally I have to do that. Good Luck and don't lose faith.
Also could be a thyroid issue, mine is slow but not enough for meds.....

You are putting your body into starvation is my guess. So your body is holding onto everything it can to keep functioning.

Probably not this unless it is day after day. Most likely what you are experiencing is water retention by your muscles to protect them from the damage exercise causes and to aid in recovery. Once your body gets use to the workouts your muscles will shed the excess water.

Please though, if you exercise eat more than 1200 cals, the amount MFP gives you to eat assumes no exercise, so when you do exercise you need to eat more to fuel your body.

I agree with this!

How long has this been happening?