The best advice as others have said is probably to take your own if possible. Not normally a fan of Gordon Ramsey but you might have a look at Plane Food because they do a onboard picnic. They might be able to do this with low carbs and it's quite convenient as it comes in it's own little bag. I have yet to enjoy one of these although I understand someone on here has. It's also airside so less chance of security removing something because it spreads.