Why Leptin (Not Willpower) Controls Your Hunger, Hormones & Healing
By Davida Syne
In July I gave an actioned-packed 2 hour webinar on this exact topic, and I have been receiving messages and emails from people who took the info and ran with it, who are already experiencing shifts in their health. One of the women I spoke shared that she lost 4 pounds within 3 days after implementing the nutritional and circadian recommendations I offered. This is the power of great info combined with ACTION! I will be releasing the replay for purchase soon - so stay tuned! In the meantime, I wrote this article to give you an intro to the concept.
If you’ve ever felt like your body is ignoring you—like you’re making tons of efforts to eat and live healthfully, and still not seeing results in the realm of weight loss, hormones, thyroid and gut function—this might be the most important article you read this year.
I promise you, your body isn’t broken - there are just some key signals that are misfiring.
And the hormone at the center of it all? It’s not insulin. Not thyroid hormone. Not estrogen.
It’s leptin—your metabolism’s master regulator.
Leptin is the hormone that tells your brain:
“We’re fed. We’re safe. We can thrive now.”
But when this signal gets jammed—through stress, poor light exposure, undernourishment, or mistimed eating—you lose that vital communication between brain and body.
You either store too much… or can’t store anything at all.
And suddenly, everything starts to feel hard.
What Is Leptin, Really?
Leptin is a hormone secreted by your fat cells. But don’t let that fool you—this isn’t just about fat.
Leptin’s job is to relay information about energy reserves to your brain, specifically your hypothalamus. It helps regulate:
Hunger and fullness
Metabolic rate
Reproductive hormones
Thyroid signaling
Sleep quality
Mood and nervous system tone
It’s not a side character. It’s the conductor.
When leptin is in balance, you eat, you feel full, you move, you rest, and your body adapts to stress with resilience.
But when leptin is out of balance?
You feel either insatiably hungry or completely disconnected from your appetite.
You store fat even in a calorie deficit.
You wake up tired, crave sugar, and feel “off” no matter how clean you eat.
This is where a lot of people get stuck.
The Role of Circadian Rhythm in Leptin Signaling
Here’s the part almost nobody is talking about: leptin is a circadian hormone.
That means it doesn’t just respond to food—it responds to light signals, time, and temperature.
Your body is designed to operate on a 24-hour clock, with hormones rising and falling based on environmental cues. These include:
Sunlight exposure (especially in the morning)
Meal timing (especially within the first hour of waking)
Sleep-wake cycles
Body temperature fluctuations
Leptin doesn’t exist in isolation. It interacts with melatonin, cortisol, insulin, and thyroid hormone—all of which follow circadian patterns.
So when you eat late at night under artificial light, skip breakfast, or live in a state of chronic stress, you scramble those signals.
The result? A body that feels unsafe—and metabolism that grinds to a halt.
Two Faces of Leptin Dysfunction
Leptin issues can show up in two very different forms. Most people assume it’s always about weight gain—but I’ve seen both extremes in my practice.
Let’s break it down.
🚨 Leptin Resistance (High Leptin)
This is the most common pattern.
You’re producing leptin, but your brain isn’t “hearing” the signal.
This is often driven by inflammation, circadian misalignment, overeating processed foods, or chronic stress. Leptin resistance is also a precursor to insulin resistance.
Common signs:
You’re hungry all the time—even after meals. Willpower runs out as the day goes on.
You also may not be hungry in the AM and easily able to fast for hours at a time until you finally eat, at which point it’s like “breaking the seal”
You gain weight easily, especially around the middle
You feel flat/sluggish/puffy in the morning and wired at night
You have thyroid issues, insulin resistance, and/or PCOS
You’ve been told to “eat less and exercise more” but it never works
❄️ Low Leptin
This is the opposite problem—and just as dangerous.
Your body isn’t producing enough leptin to feel safe.
This usually occurs in people who are underweight, over-exercising, or under-eating for long periods of time.
Common signs:
Loss of period (amenorrhea)
Cold hands and feet
Hair thinning
No appetite or constant nausea
Anxiety, insomnia, and poor recovery
Difficulty gaining or maintaining weight
In both cases, the underlying issue isn’t willpower or discipline.
It’s that the body has lost its sense of safety.
Case Study 1: From Burnout to Balance
Let’s talk about a woman I worked with who came in deeply leptin resistant.
She was 30 years old and 50 pounds overweight. Her symptoms included:
Daily bloating and constipation
Sugar addiction and intense carb cravings
Heavy, painful periods
Fatigue and emotional instability
A sense of “doing everything right” but getting nowhere
We didn’t count calories. We didn’t obsess over macros.
Instead, we focused on consistency:
Appropriate nutritional signalling
Circadian alignment
Eliminating snacking and late-night eating
Blocking artificial light in the evening
Supporting thyroid and gut function alongside gentle lymphatic movement
Within 3 weeks, she noticed a shift.
She had fewer cravings. Her digestion improved. Her mood began to stabilize.
By month four, she had lost 25 pounds without restriction.
Her family noticed how much calmer, lighter, and more “her” she felt.
Her thyroid markers began to normalize, and she felt in control again.
And the best part? She didn’t even know how to cook before we started and now reported feeling comfortable meal planning and prepping with ease, and greatly enjoying her food.
This was not about perfection. It was about alignment.
Case Study 2: Rebuilding from the Bottom Up
Now, contrast that with another woman I worked with—a 38-year-old who had the opposite issue: critically low leptin.
She was underweight—by nearly 30 pounds. Her history included:
Years of intermittent fasting and overexercising
Anxiety and poor sleep
Missing period for over a year
Gallbladder dysfunction and chronic digestive distress
Constant fatigue despite “doing everything right”
Her labs confirmed it: extremely low leptin levels. Her body had shut down reproduction, slowed digestion, and entered metabolic conservation mode.
She didn’t need another diet.
She needed permission to nourish, rest, and rebuild.
We increased her food intake gently and strategically—especially protein and fat in the morning.
We dropped the fasting and shifted her workouts to more restorative movement.
We prioritized sleep, nervous system regulation, and light hygiene.
Over the course of one year:
She gained 30 pounds gradually, reaching a strong, lean, and healthy body composition
Her period came back naturally
Her energy and appetite returned
She avoided gallbladder surgery completely
Her anxiety dropped, and her body began to trust again
This is what happens when you stop chasing symptoms and start restoring the system.
Why This Changes Everything
If you’re reading this thinking, “This sounds like me,” you’re not alone.
The reason so many health interventions fail is because they don’t address the signal distortion at the root of dysfunction.
Leptin isn’t just about appetite. It’s about safety.
And safety, in the body, is communicated through light, rhythm, nourishment, and rest.
You can’t supplement your way out of leptin dysregulation. You can’t calorie-cut your way into balance. You can’t biohack your way out of a nervous system stuck in threat.
But you can reset your rhythm.
And when you do?
Weight begins to normalize
Cravings fade
Sleep deepens
Hormones stabilize
Your sense of self returns
This isn’t a quick fix. It’s a biological remembering.
Final Thoughts: You’re Not Lazy. You’re Out of Sync.
We’ve been taught that health is about discipline. And it is true that discipline can be a form of self-love.
But many of us are trying to force ourselves into health without learning to read and respond to our bodies. We’re working against the natural rhythm of our bodies instead of with them.
If your body isn’t responding the way you want it to, it’s not because you’re not trying hard enough.
It’s because you aren’t working WITH your body and allowing it to signal correctly.
When leptin is working, everything flows.
When leptin is broken, everything feels uphill.
The good news? This is fixable.
You don’t need to suffer through another fad diet or shame spiral. You need to restore the environment your body was designed for—sunlight, protein, rest, movement, rhythm.
Leptin is your internal GPS.
You just need to reconnect to the signal.
