Why Metabolism is Faster in the Winter

G'day Legend,

Fresh off speaking in West Palm Beach at the Eudēmonia Summit, it felt wild to step off stage into 85°F heat — then land back in a brisk NYC November. That contrast got me thinking about how the body adapts to environment.

This week we’re diving into how the cold season affects your metabolism and microbiome — and what that means for how you should eat, train, and recover.

In this week’s newsletter (4 min read):
🔥 Your metabolism actually speeds up in cold weather
 🦠 Your gut microbiome changes between summer and winter
 🥣 Three performance-driven actions to make the most of it

If you’ve got a mate who’s always asking how to have more energy (without another coffee), send them THIS link and make sure they accept, so you score referral rewards.

Your Metabolism Isn’t Slower in Winter — It’s Firing Harder

If I told you that your metabolism increases in winter, would that surprise you?

Most people associate cold months with feeling sluggish, but physiologically the opposite is happening. When the temperature drops, your brown fat (the same stuff activated during a cold plunge) switches on.
It burns glucose and fatty acids to produce heat — a process called non-shivering thermogenesis.

• A 2014 study by the Journal of Clinical Investigation found that 6 weeks of mild cold exposure (19°C) increased energy expenditure by ~7%

• In 2013, Diabetes found that daily cold exposure increased calorie burn by 100–200 kcal/day

• Finnish field studies showed up to 10% higher BMR in January vs July

So yes — your basal metabolic rate rises slightly (≈5–10%) when it’s cold. But since we spend most of our time indoors, it’s not a reason to overeat — it’s a cue to eat smarter for energy stability and digestion.

Your Gut Shifts With the Seasons Too

Cold weather doesn’t just change your metabolism — it changes your microbiome.
Studies in both the U.S. (Science, 2014) and Ukraine (BMC Microbiology, 2020) found clear shifts in gut bacteria composition between summer and winter — even when diet stayed mostly the same.

Why?

• Different produce and fiber availability

• Changes in sunlight, circadian rhythm, and time indoors

• Shifts in energy expenditure and thermoregulation

Your gut is like a seasonal ecosystem. It adapts to what you feed it — and how you live.

Three Performance-Driven Actions for Cold-weather Eating:

1️⃣ Eat for Warmth and Microbial Diversity

When produce variety drops in winter, your gut loses some fiber diversity — so you have to get creative.

Target: Aim for at least 30 different plants per week.
That includes legumes, herbs, nuts, seeds, grains, and fermented foods.

Why? More plant diversity = more microbial resilience.

🥣 Example day:

• Oats + berries + flax (breakfast)

• Lentil soup with carrots + kale (lunch)

• Brown rice + salmon + kimchi (dinner)

2️⃣ Prioritize Protein and Thermogenic Nutrients

Protein has the highest thermic effect — meaning it literally burns more calories to digest. Combine it with nutrients that support thyroid and brown-fat activity (iodine, selenium, iron).

Target:

• 1.6–2.2 g protein per kg bodyweight daily

• 2 servings of seafood per week (iodine + selenium)

• Iron-rich foods like spinach, lentils, or grass-fed beef

Alma is super helpful on this point— It uses your wearable’s training data to adjust your protein target dynamically — not by guesswork.

🍛 Example: Post-run, Alma might bump your daily protein from 130g → 145g to match your output and recovery score.

3️⃣ Hydrate Like It’s Hot Out (Because You Still Need To)

Cold air dries your respiratory system, and we tend to under-drink when it’s cold. Even mild dehydration (1–2%) reduces performance and digestive efficiency.

Target:

• 35–40 ml water per kg bodyweight daily

• Add 500 ml for every hour of outdoor training

• Include electrolytes (especially sodium + magnesium) when sweating less but breathing cold dry air

☕ Pro tip: Warm fluids count — herbal teas, broths, or hot lemon water all support hydration and digestion.

Legendary Takeaway

Winter isn’t when your body slows down — it’s when it shifts gears.
Your metabolism subtly increases, your gut composition changes, and your hydration needs rise quietly in the background.

If you match those shifts with smarter nutrition, your energy stays consistent — and performance thrives year-round.

RECIPE: Spaghetti Bolognese

I’ve made this recipe every week since I was 12 — that’s about 1300 times. It’s the perfect cold-weather recipe to warm you up. Plus, it’s high in protein.

Nutrition Breakdown:
cals: 720 • fat: 26g • protein: g 42• carbs: 70g

Black Friday Specials: Alma + BPN

ALMA:
For this weekend only — get 50% off a year of ALMA Premium.
You’ll unlock advanced nutrition insights and micronutrient tracking.

🎁 Use code ALMAFEAST50 to unlock
→ Join Alma Now

BPN:
All BPN products are 20% off for their Black Friday sale — but it ends tonight so don’t miss out! Perfect time to stock up on supplements or get some gifts for your training partner or teammate. Shop now.

Quick Notes

🏃🏻‍♂️ Officially less than a week out from HYROX Dallas. Episode 3 of my HYROX World Championships training is live and it breaks down the top 5 protein hacks for performance. WATCH IT HERE.

🎁 We’re going to extend the November referral challenge through next week! You can win a BPN or AG1 prize pack worth $100! Winner announced next week. 1 referral = 1 entry. Click the link below:

#EatGoodFeelGood

— DC