medical grade food supplements

where to buy in Japan medical grade food supplements for nutrition and weight maintenance

looking for products available in Japan that meet the needs of medically compromised and undernourished patients.

i.e. 2 calorie per ml products fortified with essential macro and micronutrient needs

What brands/product names?

It may be a bit off topic, but I take moringa powder and moringa tea.
Depending on the disease, it can have the opposite effect. Not suitable for pregnant or breastfeeding women.
Benefits of Moringa
https://en.wikipedia.org/wiki/Moringa_oleifera
I have never used it, but general supplements can be purchased on iherb.
https://jp.iherb.com/

By the way, I've been drinking my own urine almost every morning for two years for my health.
This book is a good reference for urine therapy.
https://www.amazon.co.jp/-/en/Jennifer-Armstrong/dp/0091906601/ref=cm_...

Meals are based on natural hygiene.
For more information on natural hygiene, click here.
https://www.amazon.co.jp/-/en/Harvey-Diamond-ebook/dp/B083JYFJVG/ref=s...
After starting natural hygiene, I started eating fruit for breakfast. (also green juice)
I almost stopped eating meat and dairy products.

Sounds like you should go to your doctor and get her/him to advise you what to buy.

Alternatively bring the ones you are currently using in their original package to a pharmacy and ask them if they have similar products.

I wonder if you are looking for some highly nutritional food/food supplement for senior people - I know of Nestle Health Sciencefs ISOCAL jelly in packs, and Meiji Foodsf Meiji MEI Balance product range. Good for senior people who needs extra calories and protein though they cannot eat a lot.

Those are available at drugstores, large supermarkets (with a section dedicated to senior support products), as far as I know. Best wishes.