I do not think it is water weight. Over the long run, this cancels itself out. We are talking 30 years here. Have you been recording your calorie intake? How many calories do you eat on your typical day? Have you found yourself going off of your diet from time to time? You will only know this if you accurately logged every calorie. All diets do is make themselves attractive to the dieter. If a diet keeps you on track, then it works.

It all comes down to the daily calorie intake, and nothing else. A typical person maintains there weight by consuming about 2080 calories a day. If you want to lose a pound a week, then you need to eat around 1500 calories a day. One pound of fat is 3500 calories. You need to measure out or weigh the food you eat. Getting a food scale is a good idea. Some form if exercise can help. You can exercise more once you have lost enough weight for this. What is interesting is when you cut calorie consumption your body adjusts to this by slowing your metabolism. So this can work against you, but I think it is still doable. You will remain hungry during much of the day for awhile. You need to get used to this. Allot of salty foods can make your body retain water. Also if you eat some forms of ruffage, the same thing can happen.

I definitely would weigh yourself every day or every other day. Not doing this is just avoiding the problem you are trying to solve. Only in this way will you be able to see your weight change, and also see false spikes up or down which happens from time to time. If you continue to gain weight or remain the same by the end of the week, you will then need to cut your food consumption further. I have seen people eat only 1200 calories a day. Some intermittent fasting can help too.There are different ways to do this that does not involve starving yourself for a week. That is definitely not the way to go. Besides not working, this is IMO very unhealthy and unnecessary.

So I recommend that you log calories for each and every item you eat. Weigh yourself frequently every week. And then adjust your calorie intake accordingly. This will take some time to figure out and reliably do this. Focus and discapline are paramount here. Programs like Weight Watchers can help you with this in your efforts to lose weight along with the support of other people there to do the same. Oh yes, stay away from treats, food that comes with allot of calories, like mashed potatoes and pancakes with syrup, and stop drinking soda. There are foods like salads fill you up with very little in calories. Use salad dressing sparingly. Pickles also do not have much in calories. I have found juicing as a way to diet. However, this can get expensive. Once you get to your goal, you then need to gecome familar with which foods and portions to eat. Even when you are at this point, IMO you will still need to weigh yourself, like perhaps once a week.

PS It just takes time to move past the plateau. Some people think they have stopped losing weight, but if they measured their waist, the may find it still is shrinking.

FWIW