How Holiday Eating Patterns Disrupt Mood, Energy, and Sleep

For many people, the holiday season brings late nights, big dinners, random snacking, and sleep that’s all over the place. Clients often come back in January saying their anxiety has “returned.” In reality, what they’re feeling is usually a very normal physiological response to circadian disruption, irregular eating, and blood-sugar swings. Here, we're going to explain the science behind these changes, and some simple pointers to help bring things back into balance.

Late Nights + Irregular Eating: Why Timing Matters More Than the Meal Itself

During the holidays, mealtimes shift. Dinner happens at 9pm instead of 6. People graze through the afternoon. A big dessert lands at 10pm. Most clients assume the content of the meal is the issue — but the timing matters just as much.

The body’s circadian rhythm regulates insulin sensitivity, digestive hormones, cortisol release, and even core temperature. We’re biologically primed to metabolise food during daylight hours, not close to midnight.

• Insulin sensitivity is highest in the morning and lowest at night. Late meals make glucose regulation harder and more erratic [1].

• Research shows that shifting meal timing by just a few hours can shift the body’s peripheral clocks — the clocks in the liver, gut, and pancreas [1].

• When those clocks drift away from the brain’s circadian rhythm, a metabolic mismatch occurs.

  
  

This mismatch can show up as:

• higher nighttime cortisol

• lighter, more fragmented sleep

• next-day fatigue, irritability, and increased anxiety sensitivity

It's not “bad behaviour.” It’s simply what circadian biology does when the schedule is off.

2. The Physiology of Sugar: What’s Actually Happening?

Holiday food often means more sugar — in drinks, desserts, and snack plates. The issue isn’t just that sugar is “unhealthy.” It’s the speed with which the body has to respond.

A rapid rise in glucose triggers a strong release of insulin. Insulin then overshoots, and blood sugar falls fast.

This crash activates:

• adrenaline

• cortisol

• autonomic arousal

To the brain, this can feel like:

• shakiness

• heart racing

• irritability

• dread or unease

• heightened threat sensitivity

If this happens right before bed, clients may notice racing thoughts, restless sleep, early waking, and reduced REM — all of which make emotional regulation harder the next day.

3. Why Sugar Fuels Inflammation (Even the “Natural” Kinds)

This is often the part clients haven’t heard before. High sugar intake triggers inflammatory processes through several pathways:

a) Glycation + oxidative stress

Excess glucose binds to proteins, forming AGEs (advanced glycation end-products). AGEs increase oxidative stress and inflammatory cytokines [2].

b) Gut–brain axis changes

Sugar can shift gut microbiome composition within days, increasing intestinal permeability and systemic inflammation. This activates stress-reactive immune signalling — something anxious clients are particularly sensitive to.

c) Neuroinflammation

Cytokines like IL-6 and TNF-α can cross the blood–brain barrier and interfere with serotonin synthesis, glutamate–GABA balance, and HPA-axis regulation. Result? Lower stress tolerance and greater emotional reactivity [3].

d) Artificial sweeteners

Even when they don’t produce glucose spikes, they still alter the gut microbiome and can increase inflammatory signalling.

The key message for clients: Inflammation is not about “being unhealthy.” It’s about the body being in a reactive state — and that state heightens anxiety.

Why It All Feels Worse in December

Clients often blame themselves for feeling overwhelmed, anxious, or “unsettled” during the holidays. But physiologically, they’ve got a lot working against them:

• later nights

• irregular meals

• more sugar

• disrupted sleep

• more social stimulation

• more alcohol

• less daylight exposure

• higher general stress

It’s not that their anxiety has “returned.” Their body clock is dysregulated, their glucose regulation is chaotic, and their emotional systems are running on less sleep and more cortisol. A more compassionate framing makes a big difference.

How Clinicians Can Use This Knowledge

Instead of lecturing about diet, the goal is to help clients make small, stabilising changes:

• Anchor the first and last meal at consistent times.

• Pair carbohydrates with protein and fibre to soften glucose spikes.

• Encourage daylight exposure in the morning to reset circadian rhythm.

• Keep late-evening meals smaller when possible.

• Use breathing tools or VR calming sessions to downshift the stress response before and after big meals.

• Normalise that holiday patterns are temporary and easily recalibrated.

Here at oVRcome, we often remind clients that well-being isn’t about perfection — it’s about understanding how the body works and giving it small nudges back toward balance.

References

[1] Morris, C. J., Yang, J. N., Garcia, J. I., Myers, S., Bozzi, I., Wang, W., ... & Scheer, F. A. (2015). Endogenous circadian system and circadian misalignment impact glucose tolerance via separate mechanisms in humans. Proceedings of the National Academy of Sciences, 112(17), E2225-E2234.

[2] Nowotny, K., Jung, T., Höhn, A., Weber, D., & Grune, T. (2015). Advanced glycation end products and oxidative stress in type 2 diabetes mellitus. Biomolecules, 5(1), 194-222.

[3] Turnbull, A. V., & Rivier, C. (1995). Regulation of the HPA axis by cytokines. Brain, behavior, and immunity, 9(4), 253-275.