The general advice is to try new cuisines, and to add more herbs and spices. For my aging father, I am looking for condiments and foodstuffs with a strong, distinctive taste that he could add to sandwiches and meals, in a easy way.
Miso paste. A Japanese staple that gets its strong taste from a bacterial culture. Can be used as a soup base, or to be spread on a sandwich in combination with another savoury topping. Miso - Wikipedia
Likewise Marmite, a yeast extract, has a strong and distinctive taste, but not everyone likes it. (That’s an understatement.;)) German Vitam-R is similar.
My dad loved horseradish his whole life and was known to almost eat it by the spoonful. When I introduced him to wasabi (the cheap dyed green fake stuff), he also enjoyed it greatly.
I’ve got those yeast flakes, they’re a cheese substitute for vegans. They don’t have a strong taste though.
Marmite and Wasabi, of course!
What kind of entry-level hot sauces do elderly like? We don’t know the fifference between tabasco and shiracha and what else, and I cant’t buy several just to try out.
If he is better at drinking than eating you can sneak a lot of nutrition in to shakes, sweet or savoury. They sell tins of powder especially for this purpose but a plain protein powder isn’t a bad base to add to.
If he is really having trouble with food a little cannabis can help a lot if it is legal in your jurisdiction. I recently joked with a friend with late stage cancer who was hesitant to eat a brownie that it was why family sized pizzas and home delivery were invented. She declared it a miracle later.
For sandwiches etc there are any number of pickles, relishes and chutneys depending on his tastes, many go great with cheese. Roasted garlic makes mashed potato interesting and caramelised onion goes with a lot of meat, I add a bit of chilli for zing.
My dad also liked blue veined cheese ( with sweet jams/jellies) and limburger cheese. Those have a really strong taste, are cheap, and a little goed a long way.
Thank you for the recommendations, these are great!
Red wine vinegar adds a nice sharpness and zing to salad dressings or sauces. Mixed with a bit of brown sugar and ketchup it makes a nice meatloaf topping to spice up a traditional comfort food.
Indian condiments like mango chutney and lime pickle are really strong (especially lime pickle…mmm, I love that stuff). They can go on sandwiches or alongside most anything.