Hi It is never too late. First you need to understand that your yo-yo dieitng has slowed down your metabolism - this means you need far fwer calories to maintian your weight and eating a normal level of food can cause you to gain weight - which is probably what has happened. Read a book called the Maffetone Method by Dr Phillip Maffetone - it explains how walking can help you build an aerobic base and burn fat instead sugar, and get your metabolsim working better. His theroy is particularly appropriate for those with a sluggish metabolism. Exercising is so important but not strenuous exercise (at least at this stage as that will cause you to burn sugar, not fat) - you need to move not matter what. You can also eat foods that are good for your metaoblism like sea vegetables which support the thyroid and coconut oil with medium chain tryglycerides to help stimulate thrermogenesis. You need to lower stress which also can cause you to burn sugar, not fat and eat a nutrient dense diet so lots of whole grains and legumes, frutis and vegtables and good protein sources. If you find yourself overeating, you need to find out why? Emotional eating will not help you. But if you are not overeating, than you have a true low metabolism. A friend of mine runs a program call WOW! Weight Loss and it is a sane sensible program to help build lean muscle mass, which you need to have a good metabolsim and it helps you develop good eating habits that you can utilize for the rest of yoru life. Good luck.