This topic comes up a lot. I have seen the same question asked 100 different ways. This is not working - I am in starvation mode - I need to eat more, (starvation mode is real but way over blown as a cause of no weight loss IMHO), it is my genes, my metabolism is abnormal ... you name it. I am not making fun of those ideas at all. I have had all of them myself many times for years. I had a guy tell me the 3 biggest obstacles to change all took place between our ears. Rationalization, minimization and justification.
The numbers recorded in a food log -either on paper, at fitday or myfooddiary.com or anywhere for that matter are estimates. Think about it - from your RMR unless you have it tested, to the activity factor they use, to the exercise you do, even the food you log is at best an estimate. MFD and on-line food logs are tools. I happen to think they are great tools. However, like all tools used for estimation - you have to match prediction to reality.
For example - if you stay in the weight loss zone and don't lose weight there are a number of things that could be going on.
You could be retaining fluid. If so, wait a few weeks and look for trends. Are you trending down? If you scale is still not moving - now we have to look at all of the places our estimate of the real world may be off. One thing you can be assured of - no one is going to void the law of thermodynamics. Calories in vs calories out works for every human on the planet.
(There are some rare medical conditions that can impede weight loss, thyroid for example) In my opinion, your diet (I use that in the sense of what you eat - not some plan you go on and off) is only 1/2 the equation. Exercise and physical activity are excellent and very complimentary methods of creating a calorie deficit.
Things to check -
1.) Is the RMR base rate correct. You can have this tested for about 50 dollars. If not, send in the correct number and see if that fixes the problem.
2.) They use a life activity factor that they multiply your RMR by to get your maintain weight number. I think for sedentary they use 1.25. It scales up for super active people - think full time regular army to 2.0 I believe. It may be higher. That estimate could be high. I work as a programmer. 1/1/2 hour a day commute, followed by 8-9 hours typing. I am not sure 1.25 the right number for me. I think it is closer to 1.15 - you need to really look at your daily activity and see if your number seems "real".
3.) Are you logging everything and of the things you are logging - how precise are you being? There was a study that looked at people that kept food logs. They found that across the board, they under estimated their actual calorie intake by between 250 and 1000 calories per day - with the average being 395 calories. Keep in mind, that is people like us TRYING to log accurately.
4.) Exercise calories - really this has to be the most subjective of all. Your intensity is key. Heart rate monitors are good and they do help but again they are an extrapolated number (estimate) of the O2 consumption based on heart rate. If you are logging 600 calories of exercise and in reality it is only 400 combined with other errors can end up with a mysterious - I am doing everything right and no weight loss.
The real deal bottom line - never go below 1200 calories gross if you are female and 1800 male. Try to lose weight eating as close to the suggested calorie number as possible. You want to lose weight while eating as much nutritious food as possible - with in reason. If you have eliminated any health issue and you are still not losing weight - start checking the above items. When you hit a true calorie deficit, you will lose weight over time. Weight loss is not linear - you can go for a few weeks with no loss. However, if you have a calorie deficit you WILL see a loss over time.
I went back and looked at my 6 month weight loss. 29 pounds over the last 26 weeks. I have been trying to lose 1 pound per week. There have been weeks when I gained a pound, weeks when I did not lose, weeks when I lost 2 pounds and weeks when I gained and lost the same darn pound over and over. You just can't look at anything but your overall trend. Make sure you have checked all the factors listed - get to a real and safe calorie deficit and with out a doubt, you will lose weight.
The last thing I would like to say is that when you really dig down to what your goals are - it is not really a number on the scale or a dress or pants size - it is your fitness. Your quality of life. I don't think any of us wants to hit some magic BMI weight only to find we have lost all of our muscle and while we might only weigh a "normal" weight, we are what people refer to as "thin" fat people. We have no endurance, strength and are set for rapid weigh gain. If we are going to make the journey to fitness, lets take the road that leads to strong healthy bodies and minds. I know we can all achieve that goal!
I wish everyone the very best!
If I can ever help anyone, please let me know.