Lost 12 lbs then life got in the way - AGAIN!

Hi everyone. I'm Sabrina and at 44 I've been through a host of diets, gyms, and trainers (even lost to 125 lbs but gained it back). I started not to post a pic but wanted a reminder of why I'm doing this. The pic you see is with my second grandson 2 years ago; I now have 4 grandchildren and still weigh about the same as in that pic. I've noticed I'm always hiding behind people in photo, or asking for face shots only. I am using fitbit, myfitnesspal, a nutritionist, gym, and this community to hopefully shed these pounds once and for all. Question: Does anyone know what a 5/2 (may have been 5:2) plan is? I know to eat small, frequent meals, but I read this on someone else's introduction and am curious. Thanks!