Does RISE Break a Fast? A Circadian and Biological Perspective

One of the most common questions we are asked about RISE is: "Does it break a fast?"

The simple answer is yes. From a strict physiological standpoint, RISE does break a fast due to the metabolic and neurological responses it initiates. However, the real answer is far more nuanced when considered through the lens of circadian biology, evolutionary patterns, and the diverse goals behind fasting.

Understanding Fasting Through a Biological Lens

Fasting is not simply a wellness trend; it is a deeply conserved biological behaviour observed across mammalian species. Feeding and fasting cycles in mammals are governed by circadian rhythms, the internal timekeeping systems that align physiological functions with the 24-hour light-dark cycle. For humans, as diurnal mammals, this translates to a biological expectation of feeding during the daylight hours and fasting during the night.

Light exposure upon waking triggers the cortisol awakening response and sympathetic nervous system activation, priming the body for movement, energy expenditure, and nutrient intake. These are the hours when metabolic efficiency is highest: insulin sensitivity peaks, digestion is most active, and cognitive performance is most reliable.

In this context, fasting is not only about the absence of food, but also about the timing of food intake. Eating in alignment with the body's active phase supports metabolic and hormonal regulation more effectively than simply prolonging fasting duration.

Intermittent Fasting and Circadian Timing

The 16:8 intermittent fasting model (16 hours fasting, 8 hours feeding) is widely popular and increasingly supported by scientific literature. However, its success depends largely on when that eating window occurs.

Research shows that eating earlier in the day, such as between 10am and 6pm, better aligns with the body's circadian rhythm and improves insulin response, energy metabolism, and overall metabolic health (Charlot et al., 2021; Świątkiewicz et al., 2021).

Conversely, eating late in the day or at night when melatonin begins to rise can impair glucose metabolism, increase fat storage, and disrupt the synchrony between central and peripheral clocks (Shim et al., 2024; Liu et al., 2021).

While the ideal fasting pattern is to begin eating shortly after sunrise, when the sympathetic system activates and the body is biologically primed for food, many people adjust their fasting windows to suit lifestyle demands. A 10am to 6pm window, for instance, allows for family meals and social routines while still maintaining circadian alignment.

How RISE Interacts with Fasting Goals

RISE is formulated to support the biological transition from rest to wake. It contains ingredients such as creatine, natural caffeine from coffee bean extract, coconut water powder, B vitamins, and choline. These activate both the central nervous system and peripheral metabolism, stimulating mitochondrial activity, neurotransmitter synthesis, and ATP production.

For those following fasting protocols aimed at autophagy, gut rest, or calorie restriction, RISE would be considered as breaking the fast. It initiates a measurable physiological response and provides low-calorie substrates that are metabolised by the body.

However, for individuals whose fasting goals include energy enhancement, mental clarity, or metabolic consistency throughout the active phase, RISE can be a powerful tool. It supports the natural circadian transition into sympathetic dominance and complements the body's expectation of morning fuel.

Rather than contradicting fasting, it may reinforce its benefits when used with strategic timing.

Circadian Synchronisation and Dietary Timing

Numerous studies have highlighted the role of circadian synchronisation in maximising the health benefits of dietary choices. Time-restricted eating, when aligned with natural light cycles, improves metabolic markers, reduces the risk of cardiometabolic disease, and supports cognitive performance (Moon et al., 2020; Liang et al., 2022).

Mismatched eating patterns, particularly late-night or irregular meals, can disrupt this harmony, impairing glucose regulation and promoting inflammation (Nakazawa et al., 2025; Zhang et al., 2025).

By consuming RISE early in the day, especially in proximity to sunrise, users may benefit from enhanced metabolic alignment. This timing mirrors the evolutionary pattern of feeding during the active daylight phase, offering the cognitive and physiological support the body expects upon waking.

Personalisation Is Key

The question of whether RISE breaks a fast is ultimately one of context. If your priority is autophagy or gut rest, delaying RISE until your eating window begins may be appropriate. But if your focus is performance, cognitive function, or circadian alignment, RISE is likely a helpful addition to your morning routine.

The most effective fasting strategies are not rigid. They are adaptive, biologically informed, and responsive to both internal rhythms and external lifestyle demands.

References

• Moon et al. (2020). Beneficial Effects of Time-Restricted Eating on Metabolic Diseases. Nutrients, 12(5). https://doi.org/10.3390/nu12051267

• Pickel & Sung (2020). Feeding Rhythms and Circadian Regulation. Frontiers in Nutrition, 7. https://doi.org/10.3389/fnut.2020.00039

• Świątkiewicz et al. (2021). Time-Restricted Eating and Metabolic Syndrome. Nutrients, 13(1). https://doi.org/10.3390/nu13010221

• Charlot et al. (2021). Aligning Food Habits with the Circadian Clock. Nutrients, 13(5). https://doi.org/10.3390/nu13051405

• Shim et al. (2024). Circadian Rhythm Analysis via Wearables. NPJ Digital Medicine, 7(1). https://doi.org/10.1038/s41746-024-01111-x

• Liu et al. (2021). Daily Rhythms in Protein O-GlcNAcylation. Nature Communications, 12(1). https://doi.org/10.1038/s41467-021-24301-7

• James et al. (2024). Prolonged Nightly Fasting and Cognitive Function. Journal of Clinical and Translational Science, 9(1). https://doi.org/10.1017/cts.2024.676

• Chen et al. (2024). Changes in Sleeping and Eating Patterns. Food Science and Human Wellness, 13(6). https://doi.org/10.26599/fshw.2023.9250038

• Liang et al. (2022). Cophasic Rhythms in Circadian Neurons. PNAS, 119(17). https://doi.org/10.1073/pnas.2109969119

• Nakazawa et al. (2025). Neuropeptide Y and Circadian Rhythms. Bioengineering, 12(2). https://doi.org/10.3390/bioengineering12020192

• Zhang et al. (2025). Chronic Jet Lag and Liver Rhythms. Journal of Biological Rhythms, 40(2). https://doi.org/10.1177/07487304241311328