अब्भक्षा वायुभक्षाश्च फलाहारा दृढव्रताः |
दुर्बला हि बलीयांसो विप्रा हि ब्रह्मतेजसा ||

– आदिपर्व


“Despite they look lean/thin in appearance, those who are observing steadfast tapas in life and keeping food regime restricted to फलाहार (Fruits) or निराहार (उपवास), they are mighty powerful, thanks to ब्रह्मतेज.”

Not sure about others but I have experienced this. Toxic fat burns easily if you are doing daily homa and having very basic diet routine. Not sure about ब्रह्मतेज as current life complexity does not offer much room for steadfastness.

You start worshiping and respecting different forms of अग्नि and in response, the transformation is noteworthy, even for ordinary गृहस्थ(s) like us.