Fig. 1. Experimental design.

The Personalized Responses to Dietary Composition Trial (or “PREDICT1”) is a two-country (UK, US) longitudinal study whose primary goal is to predict metabolic responses to foods based on the individual’s characteristics, including molecular biomarkers and lifestyle factors, as well as the nutritional composition of the food⁸. PREDICT1 consists of one clinic baseline visit followed by a two-week home-based study. During the at-home phase, participants consumed multiple standardised test meals differing in macronutrient composition, while wearing an accelerometer wristwatch and a continuous glucose monitor. The former was used to determine sleep/wake activity during the night and physical activity during the day. The continuous glucose monitor was used to measure postprandial glucose response. Participants also recorded their dietary intake, satiety, mood, and exercise on the study app throughout the study. The app also prompted participants to report their alertness levels on a 0–100 visual analogue scale at t = 0 minutes (time of logging of a meal) and regular intervals following the logging of a meal (see “Methods”). Source data are provided as a Source Data file. The cupcake icon, the ruler icon and the smartwatch icon were purchased and downloaded from thenounproject.com. All other icons were purchased and/or downloaded from iconfinder.com. MZ monozygotic, DZ dizygotic.