I am underweight and constantly hungry.
I tried to isolate the problem with HCL - i tried no protein diet and no fats- it is a disaster for me - i tried only fruits, then only starches like potatoes - i think they are worse than cooked meat. I decided to try fruits because i read about way diet and her claims that sugar moves intestines - but many people especially here in Europe have fructose malabsorption and eating fruits and some veggies is very bad idea - also honey.
Then i tried some raw fish called bacalhao - i think all raw fish is great but not easy to buy here - we have only frozen fish and when you defrost it nothing is left - 80% water and 20% meat. Yesterday i eat raw duck liver - it was disgusting but i eat it frozen - it was foye grass - so fatted liver from grain fed ducks - nothing to do with wild duck liver but this is what we have here.
In which country of Europe are you living?
In general, in most of the Europe you would be able to get the fresh lamb liver/heart/brain/organs. In my area, mostly Muslim Shops are selling fresh lamb meat and organs.
The quality differs. In summer, when lambs are out on the green fields, then the organs have good to acceptable quality. In winter months, quality is bad. Some times, quality also changes from one shop to another.
Nevertheless, despite inferior quality, one is able to eat them and they indeed helped me.
Later I found a source from a private shepherd in the nearby hilly area. Quality was much better there as compared to the Muslim shops, although he also fed them with grains in winter, but 100% grasses in summer.