Meal size recommendation?

[human vegetable]

Dear Jeff,

My diet is exclusively comprised of medium to low calorie density food (mostly cooked whole grains, tubers, legumes, veggies), and still I like it best to have only two meals a day. Given that I'm fairly athletic, this results in two huge meals. On the one hand, I really enjoy eating so much food at one time, and never having to stop eating without feeling full. On the other hand, I'm slightly worried that I might be overtaxing my digestion. Sometimes, I feel bloated and sluggish after a meal.

Concerning calories, I'm clearly not eating too much, as my body weight and body composition have remained stable for years. Yet, I could still try to reduce the size of my meals by increasing calorie density, e. g. by reducing the amount of cooking water when I prepare grains, or by including more milled grains, such as whole grain pasta and bread.

For orientation, what is the maximum size of a meal (i. e. volume, in ml) you would recommend for an adult male?

[human vegetable]

Dear Jeff,

as so often, my request was unnecessary. This morning, I have prepared my buckwheat porridge with less cooking water, and not only was the texture firmer and less soggy (a clear culinary improvement), but there also weren't any problems afterwards.

This clearly shows that the culprit for my digestive woes was the sheer size of my meals, which is easily amended without changing much about the foods I eat.