Why You Feel Tired and Crave Carbs in the Fall: The Science of Seasonal Biology

As fall settles in and daylight decreases, many people notice significant changes in how they feel. Mornings feel harder. Energy dips earlier. Comfort foods become more appealing. Intense workouts can feel draining. Sleep becomes more disrupted.

These shifts are not a lack of discipline or motivation. They are normal seasonal responses driven by biology.

Your hormones, metabolism, digestion, nervous system, and cravings are all influenced by light. When light changes, your physiology adapts. Supporting those shifts instead of resisting them is the key to feeling good in this season.

This article explains what is happening inside your body right now and offers grounded steps to support your energy and well-being as the seasons change.

How Light Influences Key Hormones

Light is the strongest environmental cue affecting your internal clock and many hormone pathways.

Shorter days lead to the following shifts:

• Cortisol rises later in the morning, which can make waking feel sluggish
• Serotonin levels decrease, affecting mood and appetite regulation
• Melatonin rises earlier in the evening, increasing early fatigue

These changes are part of a seasonal pattern intended to help the body slow down and conserve energy. Fall invites a more restorative and reflective pace.

Seasonal Shifts in Metabolism

As weather cools and daylight shortens, your body adjusts metabolism to:

• Maintain internal warmth
• Stabilize blood sugar
• Increase appetite for denser foods

Carbohydrate cravings commonly increase to support serotonin and metabolic function. This is a normal seasonal shift, not a problem to “fix.” Warm, protein-rich meals help keep energy steady and blood sugar stable.

Why Sleep Disruption Happens

If you find yourself ready for bed at 8:30 p.m. but awake at 3 a.m., this often indicates a circadian mismatch between cortisol and melatonin. This pattern is reinforced when:

• Evening screen exposure is high
• Meals are consumed late
• Morning light exposure is limited
• Stress remains elevated into the evening

Strong morning light cues help reset the sleep-wake rhythm and improve sleep depth.

Digestion and Microbiome Adaptation

Your digestive system is also seasonal. Cooler weather naturally slows digestive fire and intestinal motility. The microbiome composition changes based on seasonal foods.

Your gut does best in fall with:

• Warm, cooked foods
• Broths, soups, and stews
• Proteins with healthy fats
• Warming spices such as ginger, cinnamon, and cloves

These foods improve digestion and stabilize appetite and blood sugar.

Understanding Carb and Comfort Food Cravings

Seasonal decreases in serotonin and dopamine can increase cravings for carbohydrate-rich or comforting foods. This does not mean you lack willpower. It is a natural neurochemical adjustment.

Instead of restriction, focus on:

• Balanced meals
• More morning light exposure
• Nervous system regulation practices
• A consistent daily rhythm

These support more regulated hunger signals and mood stability.

How to Support Your Energy and Rhythms This Fall

The goal is not to force your body into a high-performance summer pace. The goal is to support its natural recalibration.

Below are targeted seasonal shifts that can make a powerful difference.

Morning Light Exposure

• Get outside as early as possible after sunrise
• Use red or orange lighting instead of bright overhead lights if you wake in darkness
• Consider a therapeutic light device upon waking

Recommended light therapy: Mito Red Light

Morning light helps align cortisol and melatonin for better energy, mood, and sleep.

Align Eating with Daylight

• Emphasize earlier meals rather than late-night eating
• Include protein with breakfast to support serotonin and blood sugar
• Aim to finish eating before sunset when possible

Light and food are major hormonal regulators. Aligning them creates stability.

Seasonal Exercise Adjustments

Movement still matters, but fall supports a shift in timing and intensity:

• Plan higher-intensity workouts around midday
• Incorporate more outdoor walking
• Include restorative practices such as stretching, yoga, or mindful strength work

This approach supports the nervous system and improves metabolic flexibility.

Evening Light Hygiene

• Lower lights 2–3 hours before bed
• Limit bright or blue-heavy screens
• Use blue-light blockers if screens are necessary

Protecting melatonin improves sleep depth and nighttime repair.

Herbal Support for Seasonal Transition

Herbal allies can provide additional nourishment during this shift in light, metabolism, and nervous system regulation.

Nettle Leaf: A deeply nourishing mineral-rich herb (magnesium, iron, calcium) that supports energy, adrenal function, and blood sugar stability.

Tulsi (Holy Basil): An adaptogen that supports mood, stress resilience, emotional steadiness, and serotonin pathways.

These two herbs blend beautifully as a daily fall tea.

High-quality sourcing: Mountain Rose Herbs

Other supportive options include chamomile for digestion and sleep, ginger for warmth and circulation, and reishi for immune and stress support.

Your Body Is Seasonal

Your biology was designed to shift with nature. The more you fight these rhythms, the more dysregulated you feel. The more you attune to them, the better your body performs.

Fall invites:

• Rest over hurry
• Warmth over depletion
• Grounding over intensity
• Repair over productivity

Honoring these cues supports your hormones, digestion, and energy as the days grow darker.

If you want guidance and support as you align with this season, reply to this post or reach out to learn how my Empowered Gut Reset can help you feel more regulated, nourished, and energized this fall and winter. Or sign up for a free Discovery Call to learn more about working with me today.