# Meal Timing Guidance for Sleep

User's tier (Minimal / Moderate / Maximum) comes from questionnaire. Apply matrix.

## Per-Tier Matrix

| Tier | Last meal before bed | First meal after waking | Eating window |
|---|---|---|---|
| Minimal | ≥2 h | Within 2 h | ≤14 h |
| Moderate | ≥3 h | Within 1–2 h | ~12 h |
| Maximum | ≥3 h (4 h conservative) | Within 1 h, substantive breakfast | ~10 h, weighted early |

## Goal → Tier Mapping

| Goal | Tier / approach |
|---|---|
| Hypertrophy | User-selected tier; pre-sleep casein 20–40 g compatible with all tiers |
| Fat loss | User-selected tier; if using TRE, ensure protein ≥1.6 g/kg to protect lean mass |
| Body recomposition | Moderate tier; do not narrow window at expense of total protein |
| Type 2 diabetes / prediabetes / metabolic syndrome | Override: 8–10 h window, dinner before 6–7 PM, biggest meal at breakfast |
| General health | Moderate tier |
| Athletes with evening training | Drop 3 h buffer for training-meal proximity; peri-workout nutrition takes precedence; pre-sleep casein 20–40 g recommended |

## Pre-Sleep Casein Exception

A 20–40 g casein bolus (≤500 kcal liquid) 30 min before bed does NOT violate the buffer rule. The buffer applies to full mixed meals only. Pre-sleep casein is compatible with all three tiers.

## Caffeine Cutoff

- ≥6 h before bed (default)
- ≥8 h for sensitive users

## Composition Rule

A small, lean, protein-skewed evening meal (400–500 kcal, ≤30% fat) is acceptable closer to bed than a large or fatty meal of equal kcal. When applying buffers, weight high-fat meals more conservatively.

## Override Triggers

| Trigger | Action |
|---|---|
| Nocturnal reflux | Tighten last-meal buffer to ≥4 h regardless of tier; reduce evening fat |
| Prediabetes / T2D | Override to early-TRE: 10 h window ending by 6 PM, regardless of weight goal |
| Shift worker | Standard tiers do not apply. Small night snack (~10% daily kcal) during biological night, not a full meal. Buffer rule applies to whatever sleep period the worker gets. |
| Active or historical eating disorder | Do NOT narrow window. Apply Minimal tier framing only. |

## Operating Principles

- Buffer rule applies to full mixed meals; pre-sleep liquid protein is exempt
- Composition × timing interact — fat content and meal size modify how strict the buffer needs to be
- Meal timing is a secondary lever behind energy balance, protein adequacy, and fiber

For full citations see https://json.fit/meal-timing-references.md