Having a slim waist has nothing to do with aesthetics but more with your life-span and heart health.
Ideally your waist line should be half or less your height. Its an easy and better measure than body mass index (BMI). So, forget the scales and try this.
All you need to do is measure your waist at the midpoint between the crest of your hip bone and the lowest rib. (See the video above) Try to do this at a mirror or someone doing this for you. This is usually the narrowest part of your waist.
As you take the measurement breathe out and relax and DON’T suck in your tummy or pull it really tight. Check if your measurement is more or less half your height. E.g. a person has the height of 160cm then their waist should be 80cm or less for maximum benefit.
Watch the video to see how its done.