Type STATUS to see your current hunger and physical well-being levels. The two attributes should not be confused. Hunger is the more immediate, simple-physical need/desire to devour food; it can be the result of greed, some poisoning, habitual gluttony, etc. Being very hungry impacts on your ability to take on lessons, it harms your current health, it breaks your focus, etc. It does not, however, have any deeper impact and as soon as you eat some food - whatever food that may be - your hunger will be reduced and its adverse effects stopped.
Physical well-being is a far more siginficant attribute and, it should be stressed, more fundamental to your long-term health and potency. If your well-being is anything below tip-top then your very health and mana potentials (the maximums possible) suffer. As your well-being dips further your use of skills across the board will deteriorate as your body is gradually reflecting the consequences of allowing it to suffer malnourishment for long periods of time.
Full cooked meals prepared by those with the appropriate Labours ability from fresh, well-balanced ingredients - these are the only foodstuffs that fully augment one's physical well-being (as opposed to superficial hunger). The simplest rule to follow is this: if you eat one balanced meal per day, you will never deteriorate in physical well-being. If you allow your well-being to drop markedly it will take many days (sometimes weeks) to pull yourself back to full power again since, unlike mere hunger, well-being is deeper rooted and must be nurtured back to fullness. So saying, it is also a far more gradual decline and one would have to be foolish or suicidal not to take note of warning signs and ensure the acquisition of a regular, cooked meal.
Do bear in mind, scholars, LWs and the lifelong poor, that missions exist around the land where in you may SIT and receive a nourishing meal without the need to tender coin.