Brihadaranyaka Upanishad 7:26:2 states:
तदेष श्लोको न पश्यो मृत्युं पश्यति न रोगं नोत दुःखतां सर्वं ह पश्यः पश्यति सर्वमाप्नोति सर्वश इति स एकधा भवति त्रिधा भवति पञ्चधा सप्तधा नवधा चैव पुनश्चैकादशः स्मृतः शतं च दश चैकश्च सहस्राणि च विंशतिराहारशुद्धौ सत्त्वशुद्धौ ध्रुवा स्मृतिः स्मृतिलम्भे सर्वग्रन्थीनां विप्रमोक्षस्तस्मै मृदितकषायाय तमसस्पारं दर्शयति भगवान्सनत्कुमारस्तं स्कन्द इत्याचक्षते तं स्कन्द इत्याचक्षते ॥ ७.२६.२ ॥*
The portion of this verse that concerns diet purification is highlighted. The meaning of each word is as follows:
āhāra-śuddhau, if the food is pure; sattva-śuddhiḥ, the mind is pure; sattva-śuddhau, if the mind is pure; dhruvā smṛtiḥ, the memory is strong and steady; smṛtilambhe, when the memory is good; sarva-granthīnām, from all bondages; vipramokṣaḥ, one is freed
You have to have pure food. Pure food makes the body and mind pure, and you are then able to keep the mind under control. By controlling the mind, you are able to go beyond ignorance and become free from bondage.
Sattv program encourages each participant to diligently follow diet purification, which detoxifies the body. In a healthy body, a healthy mind resides. In a healthy mind, cravings are weak. The mind is calm, which enables us to respond to situations with equanimity and courage, rather than reacting to situations impulsively. This leads to a much more peaceful and joyful experience of life.