If you diet during the day, you would be preoccupied with watching your food. In dream theory, it is widely assumed that themes which occupied your thoughts during your day, are likely to surface at night in your dreams. So you dream of dieting.
If you have sufficient money and food to sustain yourself, you would not be plagued by thoughts of dieting and food rationing. However, if you have to diet because of shortage of money and food, then your dream could be telling you that its time to take action, to change your present position. You could look for better opportunities to earn money, or a store where cheaper food is sold.
Prompt – diet from #FOWC.
