Old women will often bear the lack of food for two or three days. But take food from an athlete for a single day, he will implore the very Olympian Jupiter for whose honor he is in training, and will cry that he cannot bear it. Great is the power of habit.

[Aniculae saepe inediam biduum aut triduum ferunt; subduc cibum unum diem athletae: Iovem, Iovem Olympium, eum ipsum, cui se exercebit, implorabit, ferre non posse clamabit.]

Marcus Tullius Cicero (106-43 BC) Roman orator, statesman, philosopher
Tusculan Disputations [Tusculanae Disputationes], Book 2, ch. 17 (2.17) / sec. 40 (45 BC) [tr. Peabody (1886)]
    (Source)

Original Latin. Alternate translations:

Weak old Women oftentimes go without eating two or three days together; do but with-hold Meat one day from a Wrestler, he will cry out upon Olympian Jupiter; the same to whose Honor he shall exercise himself. He will cry he cannot bear it. Great is the Power of Custom.
[tr. Wase (1643)]

You may often hear of diminutive old women living without victuals three or four days; but take away a wrestler's provision for but one day, he will implore Jupiter Olympus, the very god for whom he exercises himself: he will cry out, It is intolerable. Great is the force of custom!
[tr. Main (1824)]

Tender old women often support a fast of two or three days. Withdraw his rations for one day from a wrestler; he will appeal to that Olympic Jove himself, for whom he exercises; he will cry out it impossible to bear it. Great is the force of habit.
[tr. Otis (1839)]

You may often hear of old women living without victuals for three or four days: but take away a wrestler's provisions but for one day, and he will implore the aid of Jupiter Olympius, the very God for whom he exercises himself: he will cry out that he cannot endure it. Great is the force of custom!
[tr. Yonge (1853)]

Feeble old women often endure hunger for two or three days. Take food away from an athlete for just one day. He will appeal to Jupiter, that Olympian Jupiter, the very one for whom he will be doing this training -- he will cry out that he can't bear it. Practice has great power.
[tr. Douglas (1990)]

Little old ladies often bear a two or three day period of fasting; but take away an athlete’s food for a day, and he will beg for relief from Jove! Olympian Jove, the one for whom he exercises! And he’ll tell you that he simply cannot bear it.
[tr. @sentantiq (2015)]

Old women regularly endure a lack of food for a period of three or four days; take from an athlete his food for a single day and he will appeal to olympian Jupiter, the very god in whose honor he trains, he will cry out that he can't bear it. The force of habit is considerable.
[tr. Davie (2017)]