It will depend on the amount of physical work one does, but since you've said you work in an office, I would say one meal a day is enough for maintaining the body healthy if you have no digestive problems. I started having one normal-sized meal per day 2 years ago and I've had no problems. I'd recommend seeing what fits for you by making gradual adjustments.
Bear in mind that the following quotes are directed at monks but, depending on one's health & working conditions, laymen are also capable of following the advice:
“And how does a bhikkhu observe moderation in eating? Here, reflecting
carefully, a bhikkhu consumes food neither for amusement nor for
intoxication nor for the sake of physical beauty and attractiveness,
but only for the support and maintenance of this body, for avoiding
harm, and for assisting the spiritual life, considering: ‘Thus I shall
terminate the old feeling and not arouse a new feeling, and I shall be
healthy and blameless and dwell at ease.’ It is in this way that a
bhikkhu observes moderation in eating.
-AN 4.37, Non-decline (Aparihāniya-suttaṃ)
“Bhikkhus, I eat at a single session. By so doing, I am free from
illness and affliction, and I enjoy lightness, strength, and a
comfortable abiding. Come, bhikkhus, eat at a single session. By so
doing, you too will be free from illness and affliction, and you will
enjoy lightness, strength, and a comfortable abiding.”
-MN 65, To Bhaddāli (Bhaddāli-suttaṃ)
And how, bhikkhus, should the nutriment edible food be seen? Suppose a
couple, husband and wife, had taken limited provisions and were
traveling through a desert. They have with them their only son, dear
and beloved. Then, in the middle of the desert, their limited
provisions would be used up and exhausted, while the rest of the
desert remains to be crossed. The husband and wife would think: ‘Our
limited provisions have been used up and exhausted, while the rest of
this desert remains to be crossed. Let us kill our only son, dear and
beloved, and prepare dried and spiced meat. By eating our son’s flesh
we can cross the rest of this desert. Let not all three of us perish!’
“Then, bhikkhus, the husband and wife would kill their only son, dear
and beloved, prepare dried and spiced meat, and by eating their son’s
flesh they would cross the rest of the desert. While they are eating
their son’s flesh, they would beat their breasts and cry: ‘Where are
you, our only son? Where are you, our only son?’
“What do you think, bhikkhus? Would they eat that food for amusement
or for enjoyment or for the sake of physical beauty and
attractiveness?”
“No, venerable sir.”
“Wouldn’t they eat that food only for the sake of crossing the
desert?”
“Yes, venerable sir.”
“It is in such a way, bhikkhus, that I say the nutriment edible food
should be seen. When the nutriment edible food is fully understood,
lust for the five cords of sensual pleasure is fully understood. When
lust for the five cords of sensual pleasure is fully understood, there
is no fetter bound by which a noble disciple might come back again to
this world.
-SN 12.64, Son's Flesh (Puttamaṃsūpama-suttaṃ)