We already know that we cannot target where we lose fat on our bodies, so the short answer to how to slim down your fingers is to eat a balanced, low-sodium diet and to exercise. However. all is not lost for us endomorphs who tend to gain weight specifically in our fingers. Grip exercises can tone your fingers in the same way that lunges tone your legs and weight training tones your arms.
The most common grip exercise is done with the spring grip (see picture), but you can also use a stress ball or tennis ball. Playing an instrument like the piano or guitar or typing on a computer keyboard can also strengthen and tone your fingers.
There is a lot of debate about whether cracking your knuckles makes them chubbier. The jury is still out on that one so it is probably best not to do it if you can help it.
Again, the main thing that will help you slim down your fingers is getting your diet in line. Make sure you stay under the recommended levels of sodium for the day, drink at least eight glasses of water, and stick to an anti-inflammation diet.