i lost some weight when i was in my 40 and again this past year, now in my 60's. same result, but two dramatically different diets. in my 40's i could still function to burn 3-4000 kcals in a day. i was biking close to 250miles/ week. it didn't really matter what i ate. now in my 60's with arthritis, i was very successful again, but this time i did it through intermittent fasting with very little change in my exercise routine which is now mostly walking.