Reference for Nedarim 98:8
רבי יהודה הוה יתיב קמיה דר' טרפון אמר ליה רבי טרפון היום פניך צהובין אמר ליה אמש יצאו עבדיך לשדה והביאו לנו תרדין ואכלנום בלא מלח ואם אכלנום במלח כל שכן שהיו פנינו צהובין
were placed before R. Judah and R. Simeon. R. Judah ate; R. Simeon did not. [Whereupon] R. Judah asked him, 'Why are [you], Sir not eating?' He replied. 'These never pass out at all from the stomach.' But R. Judah retorted, 'All the more [reason or eating them], as they will sustain us tomorrow.'<span class="x" onmousemove="('comment',' As such below, R. Judah was extremely poor; hence this was a consideration to him, though there is probably an element of humour in his retort. ');"><sup>15</sup></span> R. Judah was sitting before R. Tarfon, who remarked to him, 'Your face shines to-day.' He replied. 'Your servants went out to the fields yesterday and brought us beets, which we ate unsalted, had we salted them, my face would have shone even more.