Gained weight after starting exercise program

It definitely could be. I know sometimes when I do really well with eating for awhile and step up my workouts, I can tell I have lost inches in certain places, but the scale says otherwise. I use the scale as a guideline, but don't base my entire success off of it. I have a lot of leg muscle, and I also do weights a few times a week, so I always take that into consideration. And even just doing cardio can build muscle!

However, it could also just be water weight. I always weigh myself at the same time each weigh in, wearing the same thing.

Water. :flowerforyou:

This

If you look better and feel better and have lost inches, then by all means, just stick with it! The scale is ONE, not-so-accurate form of measurement of where you are!

I was keeping my calories at or below 1200. I lost initially, then stopped. I found once I kept my net calories over 1300, I started losing again - that's WITH eating back most of my exercise calories. I can't see your diary, but when you say "strict" that's the first thing I thought of. I agree with the water comment., I also find that the morning after I work out, I retain water, so it's only if I skip a day that I'll really see a loss.

It can be a number of things, and yes...even muscle. I hope you don't mind, I looked at a handful of your food diaries and here are a few suggestions. Cut back on the processed and restaurant foods...while you weren't always over on sodium, you had a few days you were and these things are always sodium heavy. Watch your sugar intake and the sweets...once again, not always over, but trading those out for natural sugars, like fruits will make a big difference. And, I didn't see much water! While a lot of people like to debate the 8 cups of water, I do believe it works and it will help to 'flush" you out. If you aren't drinking your water, please consider starting!
And if all else fails, switch up your workout routines a bit, shake things up and see how that works. Hope you kick this plateau soon!

No, if you're operating at a calorie deficit and you aren't strength training with HEAVY weights you aren't building (gaining) muscle. More likely the weight gain is from water or that time of the month. Be patient, keep exercising and stick to MFP's calorie goal. Also, double check your diet/fitness profile to make sure your settings are correct, especially your activity/lifestyle setting.

although cardio doesnt build muscle it most certainly makes it leaner and dencer, I think inches off is what matters so your obviously doing really well :-) I think you have to change up your routine now and again because your body adapts and stores calories due to the amount of exercise you do and learns to endure more and more overtime making it harder to burn, good luck, keep up the fab work :-)

MFP recommended me 1200 a day, I am 5 foot 2 and 157 pounds.

Is that your net amount of calories (after logging exercise)? Your body could be going into survival mode if you aren't eating your exercise calories.

Also please do not believe people that tell you that muscle weighs more than fat. It doesn't. Muscle is only more dense and more packed together than fat so a 250 pound athlete/bodybuilder will look significantly thinner than the average 250 pound man.

Yes muscle does not weigh more ten fat. A pound is still a pound. and as he said muscle is dense and packed together

It is definitely muscle gain. I've been doing cardio and some strength training for 3 months, and I gained five pounds at first. It was all muscle since I haven't been active in so long. I lost fat because I dropped two dress sizes. Now, I've lost that five pounds, plus an additional 10 (I worked out two hours a day--four days a week). Don't be discouraged--you will burn more fat the more muscle you have. Eat right and follow a good exercise routine, and if you stick with it, you will lose inches. Weight is just a number on the scale.