Pickleball

MFP doesn't just set up calorie estimates out based on their own ideas. The MFP exercise database, under the covers, uses a standard calorie estimating methodology usually called METS. MFP uses pre-existing scientific research to get METS values for exercises, and pickleball METS are somewhat still in debate (limited research to date, with various outcomes).

The good news is that if you can find a METS estimate for pickleball you feel good about, you can create your own custom exercise in MFP, and use a METS calculation to get your calories for it. Once you use a METS value to figure out how many calories you'd burn at your current bodyweight and X number of minutes, MFP will scale that value for you as your weight changes, or as you play pickleball for a different number of minutes. You'd only have to do the METS math once.

There's an non-scientist article here that includes information about recent research about pickleball METS (among other things about calorie estimates and pickleball):

https://www.pickleheads.com/blog/calories-burned-playing-pickleball

You can learn way too much about METS - what they are, how to use them, values for various activities - here, mostly only in a format only a scientist could love:

https://sites.google.com/site/compendiumofphysicalactivities/home

Given the state of research, and MFP's lack of activity in terms of adding new exercises to the official database these days, I wouldn't hold my breath about when they'll do this for you.

But if you want that to happen, the best way to encourage them would be to post the suggestion here:

https://community.myfitnesspal.com/en/categories/feature-suggestions-and-ideas

I still wouldn't hold my breath, though. Maybe if you gave them a pointer to a good METS study about pickleball? Still unlikely, probably.