Top Tips: How to Avoid the December Slump

December brings celebration, connection and indulgence - but many of my clients say although it’s fun, it can leave them feeling drained, bloated, and mentally flat. The combination of darker days, disrupted routines, and more processed foods can really take a toll on both body and mind.

If you often find yourself run down by the end of the year, the problem may not be a lack of willpower but the natural stress your body faces in winter. Let’s explore why energy and mood tend to dip during the festive season, and how you can support your resilience through food, lifestyle and mindset.

Why Energy Dips in December

A perfect storm of factors contributes to the “December slump”: shorter daylight hours, higher sugar intake, more alcohol, disrupted sleep, and less movement. Each of these impacts your energy systems, metabolism, gut health and mood in subtle but significant ways.

1. Reduced daylight and lower vitamin D
In the UK, sunlight in winter is too weak for reliable vitamin D production. Low vitamin D status is associated with fatigue, poor immune function and low mood. Shorter days can also reduce exposure to natural light, affecting melatonin and serotonin — two hormones that regulate sleep, energy, and emotional stability.

2. Blood sugar fluctuations
Festive foods are often rich in simple carbohydrates and sugars, which cause rapid spikes and crashes in blood glucose. When blood sugar drops, energy and concentration follow. 

This also drives hunger, cravings and irritability, pushing you toward another quick energy hit. Over time, these swings can contribute to fatigue, poor focus, and even increased inflammation.

3. Disrupted gut health
Heavier foods, lower fibre intake and reduced microbial diversity can all weaken digestion. Gut bacteria play a vital role in producing vitamins, supporting immunity and influencing the gut–brain axis, the communication network between your gut and nervous system. When digestion slows or becomes unbalanced, it can affect not only physical comfort but also energy and mood regulation.

4. More alcohol and late nights
Alcohol intake often increases during December, and while social drinking may feel relaxing, it can significantly affect sleep quality, blood sugar balance, liver function and mood. Even moderate amounts of alcohol can suppress restorative REM sleep, increase dehydration, and strain the gut barrier - all of which contribute to low energy and irritability the next day.

5. Heightened stress and less restorative rest
December tends to bring a busier social calendar and higher stress, whether from deadlines, family dynamics or financial pressure. Chronic stress increases cortisol, which can disturb sleep, digestion and immune regulation. The result is often a feeling of being “wired but tired”: restless at night, exhausted in the morning, and prone to cravings for quick energy fixes.

Foods to Keep Energy Steady

Nutrition plays a central role in stabilising blood sugar, supporting gut health and maintaining mood. The goal isn’t restriction, but balance: pairing enjoyment with nourishment.

Balancing Blood Sugar During Festivities

The key to steady energy is keeping glucose within a stable range. When blood sugar spikes, insulin rushes in to move glucose into cells; as levels fall, energy dips follow. Preventing those swings helps you stay focused and calm.

Try to include protein, healthy fats and fibre at every meal. Protein slows digestion, fats support satiety and cell function, and fibre helps regulate glucose absorption. Together they create sustained energy release.

• At breakfast, try warm porridge made with oats, ground flaxseed and almond butter, topped with berries for natural sweetness.
• At lunch, choose soups or stews with lentils, chicken or tofu, paired with wholegrains or root vegetables.
• At dinner, include a palm-sized portion of protein (fish, poultry, tempeh) with colourful vegetables and complex carbohydrates such as quinoa, barley or roasted squash.

If you know you’ll be having dessert or drinks later, include protein beforehand. A small handful of nuts or yoghurt with fruit helps temper blood sugar spikes and can reduce cravings later in the evening.

Supporting Mood with Food

Your mood is closely tied to your gut and nutrient status. The brain relies on steady glucose, amino acids, omega-3 fats, and micronutrients like magnesium and B-vitamins to synthesise neurotransmitters such as serotonin and dopamine.

Low intake of these nutrients, alongside gut dysbiosis or inflammation, can impair neurotransmitter balance and lead to mood changes. Diets rich in whole foods, vegetables, wholegrains, legumes, fish, and nuts, are consistently linked to lower rates of depression and anxiety compared to diets high in ultra-processed foods.

Include:

• Oily fish (or algae-based omega-3 supplements) for DHA and EPA, which support brain and mood function
• Leafy greens, seeds and dark chocolate for magnesium
• Wholegrains, eggs and pulses for B-vitamins
• Fermented foods or probiotics to support gut–brain communication

Just as importantly, avoid skipping meals. Prolonged fasting or erratic eating can destabilise blood sugar and worsen fatigue. Even a small balanced breakfast helps stabilise cortisol rhythms and energy throughout the day.

Alcohol: Enjoy Without the Crash

Moderation is key. Alcohol provides short-term relaxation but disrupts nearly every system involved in energy and immunity. It interferes with deep sleep, dehydrates the body, increases gut permeability (“leaky gut”), and diverts the liver’s detoxification capacity away from other essential processes.

If you drink:

• Alternate each alcoholic drink with water or sparkling water
• Choose lower-sugar options like dry wine, clear spirits with soda, or alcohol-free alternatives
• Avoid drinking on an empty stomach, food slows alcohol absorption and reduces its impact on blood sugar
• Support recovery with electrolytes, B-vitamins and extra hydration the next day

The occasional drink is unlikely to cause harm, but frequent or excessive intake over the festive period is a common trigger for the December slump - leading to fatigue, bloating, and poor sleep quality.

Sleep: Your Forgotten Energy Source

Sleep is one of the most underappreciated forms of immune and mood support. During sleep, the body repairs tissues, clears inflammatory by-products, and consolidates memory. Inadequate or poor-quality sleep alters appetite-regulating hormones, raises cortisol, and lowers immunity.

To protect sleep in a busy month:

• Maintain as consistent a bedtime as possible
• Limit caffeine after 12 noon
• Reduce screen exposure and bright light before bed
• Keep alcohol and heavy meals at least two hours away from bedtime
• Prioritise dark mornings with light exposure early in the day, even 15 minutes of natural light helps regulate circadian rhythm

Good sleep hygiene isn’t about perfection but creating patterns that let your nervous system reset each night.

Managing Stress and the December Pace

Chronic stress can deplete key nutrients, alter gut permeability, and disrupt hormone rhythms that affect energy. The stress hormone cortisol should rise in the morning and fall gently through the day, but persistent stress can flatten this curve, leading to burnout and fatigue.

Simple ways to counteract December stress include:

• Mindful eating: Sit down, slow your breathing, and focus on chewing. This activates the parasympathetic “rest and digest” response, improving digestion and nutrient absorption.
• Movement: Gentle exercise like walking, stretching, or yoga helps reduce stress hormones and improves blood flow and energy.
• Downtime: Build short breaks into your day. Even five minutes of calm breathing or being outdoors can help lower cortisol and refresh focus.

Your gut and brain communicate constantly. Supporting calm through stress management helps regulate digestion, immune activity and emotional balance - all essential to avoiding the December slump.

If you usually reach January feeling exhausted and foggy, this year could be different. By balancing blood sugar, supporting your gut, moderating alcohol, and prioritising sleep and rest, you can stay energised and resilient through the festive season - and start the new year on stronger footing. Don’t forget to get in touch if you’d like to start January in the best place – I’m offering January sessions from now.