Its probably not the "diet type" that is the issue, rather food choices and other things. If you eat a low-carb ketogen diet, but ignore eating enough fibers you're gonna get issues. If you eat high-carb consisting of mostly grains, you need to chew these grains 70 times before they are ready to be swallowed. If you chew grains poorly, you are gonna get GI-inflammation and it will lead to issues.