Deep dive into 12 Determination (nutrition) types and 12 Cognition types — the subtlest tools for health optimization.
What Is PHS (Primary Health System)?
PHS is the optimal nutrition system in Human Design, based on the Color and Tone of the Design Sun. This isn't a diet in the classical sense — it's the mechanics of how your specific body best assimilates food and converts it into energy.
Ra Uru Hu discovered PHS as a practical tool for beginning the deconditioning experiment. The logic is simple: if the body isn't working correctly due to improper nutrition, the mind cannot be clear, and no authority will function properly.
6 Determination Types
Determination comes from the Design Sun's Color. Each Color has two variants — left (active) and right (passive), giving 12 types:
Color 1 — Appetite
- Left (Consecutive): need to eat the same things at the same times. The body thrives on stable routine. Breakfast at 8, lunch at 1, dinner at 7 — every day.
- Right (Alternating): need variety. Never eat the same thing two days in a row. The body is stimulated by novelty.
Color 2 — Taste
- Left (Open): food should be simple, with minimal ingredients. Mono-meals, simple recipes, clean flavors.
- Right (Closed): complex dishes, many ingredients, complex flavors. The body needs culinary complexity.
Color 3 — Thirst
- Left (Hot): hot food and drinks. The body better assimilates warm food.
- Right (Cold): cold food and drinks. Raw products, salads, chilled food.
Color 4 — Touch
- Left (Calm): need quiet and peace while eating. No TV, no conversation, full attention on food.
- Right (Nervous): need stimulation while eating — conversation, TV, reading. Paradoxically, this improves digestion.
Color 5 — Sound
- Left (High frequency): the body works best when food is paired with high-frequency sounds — classical music, nature sounds.
- Right (Low frequency): low-frequency vibrations during meals — deep voice, bass music, or silence.
Color 6 — Light
- Left (Direct light): eat in bright lighting, preferably daylight. Sunlight stimulates digestion.
- Right (Indirect light): eat in soft, diffused light. Candles, dim light, or even darkness.
12 Cognition Types
Cognition is determined by the Personality Sun's Tone and describes how your mind best processes information:
- Smell (Tone 1) — a "nose" for the right information. Instinctive knowing whether something is correct or not.
- Taste (Tone 2) — "tasting" information. Need to sample a topic before diving deep.
- Outer Vision (Tone 3) — need to see the big picture. Learning through observation, visual materials.
- Inner Vision (Tone 4) — focus on details. Need to "see" within, meditative approach to information.
- Feeling (Tone 5) — learning through tactile experience. Need to "touch," try in practice.
- Sound (Tone 6) — acoustic cognition. Learning through listening, audiobooks, lectures, conversations.
Each cognition also has a left (focused) and right (peripheral) variation, giving 12 types total.
How to Begin the Experiment?
Calculate your bodygraph and pay attention to the upper Variable arrows. Start with Determination — change your eating conditions according to your type and observe changes over 3-6 months. Then add the Cognition experiment.
"PHS is the gateway to deconditioning. Without proper nutrition, the body cannot support consciousness in its correct state." — Ra Uru Hu


