Eating Less Kept Me Fat for 15 Years (45kg Later, I Know Why)

The worst fitness advice you'll ever receive comes wrapped in three words: "Just eat less."

I see it constantly in tech. CTOs replacing meals with black coffee, thinking caffeine is enough. Engineering managers skipping lunch to meet deadlines, telling themselves it'll help them lose weight anyway. Tech leads staying hungry all day, thinking it means the diet is working.

It's not.

I know because I tried it for years. At my heaviest—120kg—I cycled through every calorie-restriction scheme imaginable. 1,200 calories. Intermittent fasting taken to extremes. Meal replacement shakes. The result? I got weaker, foggier, and somehow still carried excess fat around my midsection.

It took me another 10 years of trial and error—trying different approaches, failing, adjusting, trying again—before I finally cracked the code. I dropped from 120kg to 74kg at age 40.

Then I became a Certified International Personal Trainer—not to make it a career, but to understand what the hell I'd been doing wrong all those years, and what actually worked.

This article isn't about feel-good nutrition advice. It's about why "eat less" is a systems failure—and what high-performing professionals should do instead.

The Metabolic Death Spiral: How Eating Less Makes You Fatter

Here's what happens when you slash calories dramatically:

Your body doesn't say, "Oh good, we're finally losing fat!" It says, "We're starving. Shut down non-essential functions and store every calorie possible."

This phenomenon is called metabolic adaptation, and it's well-documented in the research. When you reduce caloric intake too aggressively, your resting metabolic rate drops by 15-30%.¹² Your body literally downregulates energy expenditure to match the perceived famine.

But it gets worse.

Your hormones shift into survival mode. Cortisol—your primary stress hormone—spikes and stays elevated.³ Chronically high cortisol promotes visceral fat storage (the dangerous fat around your organs) while simultaneously breaking down lean muscle tissue for energy.⁴

So you're eating less, feeling miserable, and your body is actively storing fat and burning muscle. This is the metabolic death spiral that creates the "skinny-fat" physique: low body weight, high body fat percentage, zero muscle definition, and the strength of a damp napkin.

I see this constantly in tech. Smart people apply "optimization" logic to their diet: minimize input, maximize output. But your body isn't a database query. It's an adaptive biological system that interprets extreme restriction as an existential threat.

You can't hack your way past millions of years of evolutionary programming.

But here's where it gets really dark.

When you're eating less and less, and the scale still isn't moving, you start blaming yourself. You feel guilty every time you eat. You obsess over every calorie. You start hiding what you eat from people.

This guilt-shame-restriction cycle doesn't just make you miserable. For some people, it triggers serious eating disorders—anorexia, bulimia, binge eating disorder. Conditions that require actual psychological treatment.

I've worked with clients who developed these patterns after years of extreme dieting. Smart, successful people who thought they were just being disciplined—until the relationship with food became so twisted it required professional help to fix.

This isn't me being dramatic. Chronic caloric restriction rewires how your brain processes hunger, fullness, and self-worth.⁵ The death spiral isn't just metabolic. It's psychological.

Why Every Diet Fails: The Deprivation Trap

Let me ask you something: How many people do you know who maintain visible abs year-round while constantly "dieting"?

Zero.

Because that's not how it works.

But here's what nobody tells you: the fitness industry doesn't make money by getting you lean quickly. They make money by keeping you as a gym member for as long as possible.

Think about it. If you got shredded in 6 months and stayed that way—you'd cancel your membership. You wouldn't need their supplements. You wouldn't buy their meal plans.

Their business model requires you to stay below your own standard of leanness. Stay frustrated. Keep trying. Keep buying.

So they sell you deprivation. "Just eat less!" "Just have more discipline!" "Just try harder!"

It keeps you spinning your wheels. And spinning your wheels keeps you paying.

The people who stay lean year-round—real people, not fitness influencers—aren't on diets. They're not suffering.

Think Jeff Bezos. Alex Hormozi. Mark Zuckerberg. Tim Cook. These are tech leaders running companies, making billion-dollar decisions—and they're in great shape.

They've calibrated their food preferences and eating habits to naturally support their body composition goals.

Hormozi genuinely enjoys eating grilled chicken, rice, and vegetables most days. Bezos has been training consistently for decades. That's not willpower. That's preference alignment.

But here's the trap: his food preferences are different from yours. Right now, you might crave pizza, pasta, and craft beer. That gap between your current preferences and sustainable eating patterns is where most people fail.

They try to bridge it with willpower and restriction. And willpower always runs out.

Research confirms this. Studies on caloric restriction consistently show that 80-95% of dieters regain the weight they lost within 1-5 years.⁶ The psychological toll of deprivation—the constant mental negotiation, the food obsession, the social isolation—makes long-term adherence nearly impossible.⁷

This is why I don't put clients on "diets." I help them build sustainable eating systems that feel normal, not heroic.

The question isn't "How little can I eat?" It's "How do I develop food preferences that support my goals without requiring constant willpower?"

That transformation takes time and data. Which brings me to the next point.

Blind Restriction vs. Data-Driven Nutrition

There's a massive difference between eating as little as possible and eating based on actual data.

Most people don't know how many calories they consume daily. They guess. They estimate. They convince themselves that "eating healthy" automatically means fat loss.

It doesn't.

I've worked with executives who swore they were eating "barely anything" while tracking showed they were consuming 2,800+ calories per day. Their perception was completely disconnected from reality.

This is why I require every client to track their food intake for at least 3-6 months. Not forever. Just long enough to build nutritional awareness and calibrate their "food radar."

Think of it like debugging your codebase. You wouldn't optimize performance without profiling first. You need baseline metrics before you can make informed changes.

The tracking process reveals:

• The caloric density of your favorite foods
• Whether you're in a deficit, surplus, or maintenance
• Which meals keep you full vs. which leave you hungry
• How weekends vs. weekdays affect your intake
• Where hidden calories accumulate (sauces, oils, liquid calories)

Once you have this data, you can make precise adjustments. Not guesses. Not "eat less and hope." Actual engineering-level optimization.

For fat loss, I recommend a 300-500 calorie deficit—enough to drive consistent progress without triggering metabolic adaptation or hormonal chaos.⁸ This modest deficit preserves energy, maintains muscle mass, and keeps your brain functioning at full capacity.

But you can't calculate that deficit if you don't know your baseline. Start with ruthless tracking. Use tools like MyFitnessPal or the nutrition tracker from my book. Build awareness first, optimize second.

The Performance Tax: How Hunger Destroys Leadership

Let's talk about what extreme caloric restriction does to your professional performance.

Your brain consumes roughly 20% of your total daily energy expenditure—despite being only 2% of your body weight.⁹ When you're in a severe calorie deficit, your brain doesn't get priority access to fuel. It suffers along with everything else.

The result?

• Impaired decision-making under pressure
• Reduced working memory capacity
• Slower cognitive processing speed
• Increased irritability and emotional volatility
• Difficulty focusing during complex problem-solving

Now imagine walking into a high-stakes meeting with a board member or key stakeholder while running on 1,200 calories and two cups of black coffee. You think you're "powering through." What you're actually doing is operating at 60% cognitive capacity.

I've seen this play out dozens of times. The CTO who gets snappy in code reviews because he skipped lunch. The engineering manager who can't think clearly during sprint planning because she's been restricting carbs all week. The tech lead who makes a critical architecture decision while hypoglycemic and regrets it later.

You're not building mental toughness. You're sabotaging your most valuable asset: your ability to think clearly and lead effectively.

High-performance leadership requires high-voltage energy. You need:

• Sharp analytical thinking for strategic decisions
• Emotional regulation during conflict
• Sustained focus during deep work sessions
• Presence and charisma during presentations
• Resilience when managing high-pressure situations

None of that is possible when you're chronically undernourished and stressed.

Your team notices. Your peers notice. Your performance reviews reflect it, even if no one directly mentions your energy levels.

Eating less might feel like discipline. It's actually self-sabotage.

The Sleep Disruption Cascade

Here's another hidden cost of extreme caloric restriction: destroyed sleep quality.

When you eat too little, your body perceives it as a threat. Cortisol stays elevated—not just during the day, but at night when it should naturally drop.¹⁰ This disrupts your circadian rhythm and makes it harder to fall asleep and stay asleep.

Additionally, going to bed hungry triggers ghrelin release (the hunger hormone), which interferes with melatonin production and REM sleep architecture.¹¹

The consequences compound fast:

• Poor sleep reduces insulin sensitivity, making fat loss harder¹²
• Sleep deprivation increases hunger and cravings, especially for high-calorie foods¹³
• Lack of REM sleep impairs memory consolidation and emotional regulation¹⁴
• Chronic sleep disruption lowers testosterone and growth hormone, hindering muscle recovery¹⁵

You end up in a vicious cycle: eating less → sleeping worse → craving more → feeling weaker → eating even less to compensate → sleeping even worse.

I've watched tech professionals spiral into this pattern for months before realizing the root cause wasn't stress or burnout—it was chronic under-eating.

Your sleep is non-negotiable. It's where your body recovers, your brain consolidates learning, and your hormones rebalance. When you sacrifice sleep quality to maintain an unsustainable calorie deficit, you're trading short-term weight loss for long-term cognitive and physical decline.

Not a good trade.

What to Do Instead: The Performance-First Approach

Alright. Enough about what's broken. Let's fix it.

This isn't a vague "eat better and move more" platitude. This is a structured, engineering-level approach to transforming your body composition without destroying your performance, sleep, or sanity.

Step 1: Assess Your Current State

Before you change anything, you need to understand where you are right now—across all dimensions: energy levels, cognitive performance, sleep quality, fitness capacity, and current eating patterns.

Take the Performance Audit at fullstackfitness.net/audit. It takes 3-5 minutes and gives you a comprehensive analysis of your baseline physiology, mental performance, and executive presence. No calendar booking required—you get immediate, actionable insights.

Think of it like running a system diagnostic before deploying changes. You can't optimize what you don't measure.

Step 2: Start Tracking Ruthlessly

For the next 3-6 months, log every meal. Every snack. Every liquid calorie.

Use MyFitnessPal or a similar app. If you prefer analog, grab the nutrition tracker from my book 6-Pack ABS for Keyboard Warriors.

The goal isn't to judge yourself. It's to build awareness. You need to see:

• Your true daily calorie intake (most people underestimate by 30-50%)
• How much protein you're actually eating (probably not enough)
• Where empty calories hide (sauces, drinks, mindless snacking)
• Which meals keep you full vs. which leave you hungry

Track honestly. Track consistently. This data is your foundation.

Step 3: Calculate Your Optimal Deficit

Once you know your baseline intake, use the BMR Calculator at fullstackfitness.net/bmr to determine your optimal calorie target.

For sustainable fat loss without metabolic adaptation, aim for a 300-500 calorie daily deficit. Not 1,000. Not 1,200. A modest, data-driven deficit that allows you to:

• Preserve muscle mass
• Maintain energy for training
• Keep your brain functioning at full capacity
• Avoid hormonal disruption
• Sleep well

This approach takes longer than crash dieting. It also actually works.

Step 4: Remove the Junk, Keep the Foods You Love

You don't need to eat chicken and broccoli for the rest of your life. But you do need to eliminate the obvious saboteurs:

• Sugary drinks (soda, juice, frappuccinos)
• Ultra-processed snacks (chips, cookies, pastries)
• Deep-fried foods
• High-fat dairy (switch to low-fat versions temporarily)

Then learn to prepare healthier versions of your favorite meals. Love pasta? Learn to make it with lean protein and tomato-based sauce instead of cream and oil. Crave dessert? Swap ice cream for protein pudding or Greek yogurt with berries.

My book includes detailed substitution strategies and a growing recipe library designed specifically for busy professionals who don't have time for complicated cooking. The goal is to develop food preferences that naturally support your goals—not white-knuckle through deprivation.

Step 5: Add Protein to Every Meal

Protein is the single most important macronutrient for body recomposition. It:

• Preserves muscle mass during fat loss
• Increases satiety, so you feel full longer
• Has a high thermic effect (burns more calories during digestion)
• Stabilizes blood sugar and energy levels
• Supports recovery from training

Aim for 1.6-2.2g of protein per kilogram of body weight daily.¹⁶ For an 80kg person, that's 128-176g per day.

Build every meal around a lean protein source: chicken, fish, eggs, Greek yogurt, tofu, legumes. Make protein the non-negotiable anchor, then add carbs and fats around it.

This one shift—prioritizing protein—will transform your hunger levels, energy, and body composition faster than any other dietary change.

Step 6: Start Training to Build Muscle and Boost Metabolism

Here's where the magic happens.

When you add resistance training or hybrid training (strength + cardio), you:

• Build lean muscle, which increases your resting metabolic rate¹⁷
• Create demand for more calories, allowing you to eat more while still losing fat
• Improve insulin sensitivity and glucose disposal
• Boost testosterone and growth hormone naturally
• Enhance cognitive performance through increased BDNF production¹⁸

This is the "eat more, move more" philosophy in action. Instead of starving yourself into a metabolic hole, you increase your energy expenditure through training, then fuel that training with more high-quality food.

You create a virtuous cycle: train harder → eat more → build more muscle → burn more fat → train even harder.

Check out the follow-along workouts and hybrid training programs at fullstackfitness.net. You don't need a gym. You don't need hours of time. You need 15-30 focused minutes, 3-5 times per week, doing movements that actually work.

When you combine smart training with strategic nutrition, your body stops fighting you. It starts cooperating.

The Bottom Line

Stop eating less. Start eating smarter.

Your body isn't a balance sheet where you just minimize input to maximize output. It's a complex adaptive system that responds to signals—and chronic restriction sends all the wrong signals.

The tech leaders who maintain lean, strong, high-performing bodies year-round aren't suffering through perpetual deprivation. They've built systems that work with their biology, not against it.

You can too.

Start with the Performance Audit. Get the data. Build the system. Engineer your body composition the same way you engineer software: with metrics, iteration, and a long-term mindset.

Your cognitive performance, leadership presence, and career trajectory depend on it.

Ivan Aseev Certified International Personal Trainer & Nutrition Adviser | 23+ Years Leading Engineering Teams | Author of 6-Pack ABS for Keyboard Warriors

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