If you have a weight problem it seems the modern solution is to talk it over with your ZX81!
This package is quite large with two cassettes and a 22-page booklet, and your first problem is digging out the cassettes from their plastic beds. However, the book is easier to extract, and is worth reading, if only to dream of blueberry pie and baked bluefish.
Seriously though, you must read the book first because you have to prepare certain information about your eating habits before you can answer the questions on the first cassette. After the computer has digested the information regarding your age, sex, height and eating habits your own personal weight goals are assessed. Side B is concerned with producing menus based on different foods of different caloric values, giving recommended qualities and even taking your mood into account.
Because dieting is such a personal, sometimes very serious business, I can neither recommend nor condemn this program. Although I understand the program was written by a Dr. M. Minksy I can find no reference to him in the handbook.