In Ayurveda 6 tastes have been recognised within our foods:
Sweet (squash, sweet potato, fruits, many carbohydrates)
Sour (citrus fruits, fermented products)
Salty (sea/rock salt, seaweeds)
Pungent (chilli, paprika, harsh spices, rocket)
Bitter (garlic, bitter gord)
Astringent (dark leafy greens)
Like the dosha these 6 tastes each have two predominant elements:
Sweet = Water + Earth
Sour = Water + Fire
Salty = Earth + Fire
Pungent = Air + Fire
Bitter = Air + Ether
Astringent = Air + Earth
We all need a balance of these elements to stay healthy and depending on our constitutions or imbalances we may need more or less of some of them because of the elemental constitution of our dosha. For example:
Vata Dosha is aggravated by Astringent, Bitter and Pungent tastes as these all have the air element and/or the ether element which is the same as the vata dosha and so a vata individual can easily receive too much of these elements if they are regularly eating foods of theses tastes. Similarly vata is alleviated by sweet, salty and sour tastes as these are made of elements that vata constitutions are lacking in.
Pitta Dosha is aggravated by Pungent, Sour and Salty tastes (as these all have fire which is the same as the elemental constitution of the Pitta Dosha) and is alleviated by Astringent, Sweet and Bitter tastes (as these contain earth, water and air qualities which pitta is lacking in - it's important to note that even though Pitta is made up of fire and water the water is often overpowered by the fire and so Pitta individuals often need to intake water to stay in balance).
Kapha Dosha is aggravated by sweet, sour and salty tastes as these contain water and/or earth and is alleviated by bitter, pungent and astringent tastes (as these have opposing elements, even astringent as this taste is stronger in air than it is in earth).
Each of these tastes provides completely different vital nutrients necessary for the functions for our bodies and minds however in a lot of our western food we only receive one or two of them at a time. This leads to food cravings after we have eaten a meal.
For example many of us crave sweet tastes after a savoury meal because there were no naturally sweet tastes within the meal, this can easily lead to over eating because although we might be full our bodies have not been satisfied with the correct nutrients/elements yet. Or we might be addicted to coffee, wine or chocolate because we are not getting any bitter tastes in our food so we are finding them from alternative, more aggressive sources which can lead quickly to imbalances due to the concentration of bitter and/or the other substances within these foods. Coffee can quickly lead to a pitta and Vata imbalance because the caffeine is very heating, aggravating pitta and the bitter taste has a lot of concentrated air aggravating Vata.
Kapha imbalance is also common in this culture due to the excess of sweet and salty foods and the amount of concentrated sugars we indulge in regularly. These quickly lead to build up of earth and water elements in the Kapha tissues such as fat and muscle.
Think about when you eat a very flavoursome meal like a dhal with spinach, brown rice and pickle, you are unlikely to rush to the fridge for something sweet or bitter straight after because the spices, garlic and pickle in the meal has already satisfied those tastes. When we are cooking if we are aware of this we can try and include all the 6 tastes and this will help naturally calm down food cravings as well providing a healthier meal with everything we need.
However if you are suffering from a specific imbalance and are unsure of what to eat I would recommend an Ayurvedic consultation as there will likely be things that are aggravating the condition and the 6 tastes may not apply in the same way.