Maybe you haven't been so "on" with your food plan for the past few days and the scale reflects that.
Or, maybe you've been sticking to your food and exercise plan religiously and you step on the scale only to register a two pound weight gain. Uuuuugh! How frustrating.
Just know that the stuff you are experiencing on the scale is normal. Even thin people experience this regularly. Think about what you have been eating for the past many days. Think about your exercise too. There are two possible causes and only one solution.
Cause #1: You may be retaining water (so try drinking a lot more when you experience this) or getting your period soon (if you are female). Do not let it derail you! The MOST important thing is what you are putting in your body--not the number on the scale--so if you know that you are following your plan, the numbers WILL work themselves out within a week. Please know that small ups and downs on the scale over the long haul are totally normal when you are trying to lose weight. What would be unusual would be a perfect line going straight down on your weight loss graph!
Cause #2: You haven't been "on" your plan. It's that simple. Maybe it was the weekend, maybe you had an unusual number of social events in the past week. Maybe your emotional eating got the best of you. KNOW THE CAUSE! You can't fix anything if you don't know why it is broken.
Solution: Whatever the reason for your weight gain, the solution is the same:
Let it go. Resolve that TODAY will be a great food day.
You can even write down what you plan to eat all day today and how you plan on exercising. Then follow that plan. If you are in front of food that is not on your plan, say to yourself, "That food is not on my plan. I will eat the food that is on my plan." It really can be that simple. You can string great food days together one at a time. And shortly you will see the scale move in the right direction.