When 29 Starts to Feel Different: A Simple, Reproducible Cut from 75kg to 64kg

Yohei Kano (aka Hey9Woz)

Table of Contents

Introduction

  • You want to start a diet but don’t know where to begin.
  • You installed a calorie tracking app and stopped opening it after three days.
  • You care about your health check numbers, but being tied to numbers every day feels exhausting.

If any of those sound like you, this article might help.

I’ve never been “bad” at dieting.
For the last 3 years or so, I’ve been doing a pretty reckless yo-yo:

Bulk up to 75kg, then cut down to 63kg, every year.

But when I turned 29, the vibe started to change a little.

  • I catch colds more easily than before
  • When I play with my kid at full power, the fatigue sometimes lasts until the next day
  • I look at photos of myself and something just feels off

I wanted to take that “something’s not right” feeling seriously.

So from July 2025, I started a new approach:

Loose with numbers, strict with habits.

In this article, I’ll share:

  • What I actually did from July to November
  • The “templates” I use for training and eating that are easy to copy
  • My plan from November onward to focus more on body fat and body lines (and how that ties into preventing rebound)

This isn’t a “perfect method” or a universal recommendation.
Think of it as:

“Here’s how far you can go with something this simple.”

My Stats & First “Something Feels Off” Moment

Quick profile:

  • Age: 29
  • Height: 168 cm
  • Job: Brain-heavy work (software engineer)
  • Family: Wife and a young son
  • Usual weight range:
    • When I’m “fat”: around 75kg
    • When I’m “lean”: around 63kg

In late July 2025, I went back to my parents’ place with my family.
And I got the classic Japanese relatives comments:

“You’ve put on weight.”
“You look like a sea lion.”

Half joke, half truth. but That's disrespectful to both the sea lions and me.

At the same time, I already had this quiet discomfort:

  • My face line in photos was clearly rounder
  • My body felt heavy when playing with my kid
  • I was catching colds more often than before

I caught myself thinking:

“If I slide into my 30s like this, it’s going to be quietly rough.”

That was the moment I decided to properly reset my habits.

July to November: A “No Daily Weigh-in” Cut (75kg → 64kg)

Only Decide the Start and the Checkpoints

The first rule I set:

No daily weighing.

Here are the actual numbers:

  • July 2025: 75.0kg (starting point)
  • Early November 2025: 64.0kg (checkpoint)

What did I do in between?

  • Use daily mirror checks to see “hmm, a bit leaner today”
  • Keep a rough sense of “I’m probably in the xx kg range now”
  • Only check the actual number again after more than 3 months

There was one exception: my annual health check in September.

  • 2025-09-17: 69.0kg

When I saw that number, I thought:

“This is a bit too fast, right?”

So I switched to a “adjustment phase” training plan, which I’ll explain later.

Why I Don’t Weigh Myself Every Day

The reason is simple:

  • +0.5kg
  • −0.3kg

Those tiny swings are mostly water, not fat.

I didn’t want my mood to be dragged around by them.

In the end, what I actually do is:

  • Stick to my eating template
  • Do cardio and HIIT (and for some people, strength training)
  • Sleep

That’s it.
Stepping on the scale every day doesn’t fundamentally change today’s menu.
If I tried to adjust my training and food every single day based on tiny fluctuations, that would:

  • Add stress
  • Require extra time for something that is not yet a habit

So I decided:

“It takes about three months before you visually see a clear change.”

With that in mind, I treated July–September → September–November as a single cutting block, instead of watching every day.

Aerobike & HIIT: Cardio That Ignores Weather & Chaos

Why I Switched from Morning Walks to an Aerobike

In past diets, my main cardio was morning walks.

But now, with my current life, walking has problems:

  • I’m not naturally a morning person
  • Rain and cold weather kill my motivation
  • I’ve pushed myself on walks before and ended up catching a cold

And when I try to make morning walks a daily habit,
it also clashes with my family’s rhythm.

  • If my child wakes up early while I’m outside,
    my wife (who is still sleeping) has to suddenly get up and handle everything
  • Considering my own sleep,
    on nights when putting my child to bed doesn’t go well,
    waking up even earlier to go for a walk is pretty harsh

On top of that, I simply want:

“Decent sleep, if possible.”

At some point I realized:

“I’m letting my habits be pushed around by things I can’t control.”

I can’t control:

  • The weather
  • When my child wakes up
  • How smooth bedtime is going to be

So I decided to move to cardio that finishes inside the house:

An indoor aerobike.

Benefits:

  • Weather doesn’t matter
  • If my child wakes up early, I’m just in the next room
    • I can help with the toilet
    • Or say “good morning” and chat about the day
  • My wife doesn’t have to jump out of bed because I went outside
  • I can ride 20–30 minutes while watching Netflix
  • No need to worry about cars or traffic

I have this principle:

“Reduce the influence of factors you can’t control,
rather than trying to ‘power through’ everything with willpower.”

Things like:

  • Weather
  • Kids’ sleep and wake timing
  • The family’s daily rhythm

These are all things I can’t fully control.
So I treated the 1–2万円 for an aerobike as an environment investment.

The one I use is a fitness bike from ALINCO.
For a long time I honestly thought the brand name was “Arinko” (ant).

my alinco fitness bike
My ant.

Phase 1: “Push Phase” Weekly Plan (mid-July to mid-September)

This was my “let’s actually drop some weight” phase.

  • Mon: 30 min steady cardio (level 4, fat burn focus)
  • Tue: HIIT (intervals between level 3 and 6)
  • Wed: 20 min light cardio (level 3) or full rest
  • Thu: HIIT
  • Fri: 30 min steady cardio (level 3)
  • Sat: 40 min steady cardio (longer session, calorie-burn day)
  • Sun: 20 min light cardio or full rest

HIIT details (only using the first half of the video)

I use the first half of a YouTube HIIT bike workout.

One interval set looks like this:

  • 30 sec: Level 6, close to all-out pace
    • You can say short sentences, but it’s hard
  • 30 sec: Level 3, easy pace
    • You can carry a conversation, but you’re still breathing heavier than normal

I do:

  • 3 min warm-up
  • 6 rounds of that 30/30 interval
  • 4 min cool down

For the first 2–3 sessions I felt absolutely wrecked.
I played sports growing up, so I can force myself to finish.

But this time I chose:

“Rather than suffering and not losing much,
I’d rather feel good and then realize I’m leaner.”

So I intentionally stop at the first half of the video.

The video I’m using (only the first part):

Phase 2: Adjustment Phase Weekly Plan (2025-09-17 to 10-31)

At the health check on September 17, I was already down to 69kg.

I thought:

“This pace might be a bit fast.”

So I shifted into an “adjustment phase”:

Keep the same eating pattern,
but reduce training volume a bit.

Weekly plan:

  • Mon: 20 min cardio (level 4)
  • Tue: 30 min cardio (level 3)
  • Wed: Full rest
  • Thu: HIIT (level 3 & 6)
  • Fri: 20 min cardio (level 3)
  • Sat: 30 min cardio (level 3)
  • Sun: Full rest

Even at this pace, my weight gently moved from 69kg → 64kg.

Phase 3: Completion + Strength Training (from 2025-11-03 to ~Jan)

I checked my weight for three days in a row at the beginning of November:

  • 11/01: 64.0kg
  • 11/02: 63.5kg
  • 11/03: 64.0kg

Since I was now within my target range of 63–65kg, I changed focus:

From “losing weight”
to “body fat, body lines, and rebound-resistance”.

New weekly plan:

  • Mon: 20 min cardio (level 4) + 10–15 min bodyweight training
  • Tue: 30 min cardio (level 3)
  • Wed: Full rest
  • Thu: HIIT (level 3 & 6)
  • Fri: 20 min cardio (level 3) + 10–15 min bodyweight training
  • Sat: 30 min cardio (level 3)
  • Sun: Full rest

Simple At-Home Strength Routine (Twice a Week, Always the Same)

The goal is not to become huge. It’s more about:

  • Posture
  • Using my core properly
  • Making my silhouette a bit sharper

I fixed Monday and Friday as strength days.
The menu is always the same:

  1. Squat: 15 reps × 2 sets
  2. Push-ups: 15 reps × 2 sets (knee push-ups allowed)
  3. Plank: 30 sec × 2 sets
  4. Hip lift / glute bridge: 15 reps × 2 sets
  • Rest intervals: around 30 seconds
  • Target intensity: “I’m tired, but I can still go about my day normally”
  • To lower friction, I don’t change the routine. Same menu every time.

When this starts to feel too easy, I plan to adjust by:

  • Shortening rest time
  • Adding 2–3 reps per set
  • Increasing to 3 sets
  • Slowing down the movement / trying single-leg variations

There's nothing special about it, it's just easy to focus on, easy to repeat, and easy to stick to.

Eating Rules That Don’t Obsess Over Numbers

Managing Calories with “Feel + Rough Boundaries”

In reality, I’ve been eating around 1500–1800 kcal per day.
On some days I might be closer to 1300 kcal.

But I don’t use a calorie tracking app.

Reason:

I already handle numbers at work.
I don’t want to stare at numbers again every time I eat.

Instead, I do this:

  • Decide a rough daily calorie band
  • Have an upper limit image per meal
  • On days with big dinners or eating out, I skip or reduce one snack

It’s a mix of structure and feel, not precise logging.

My Typical Day (Rough Template)

Morning

  • Black coffee
  • Cardio (bike)
  • No “proper” breakfast → I go into work slightly hungry
    • For me, this actually improves my focus in the morning

Around 10:00 (Snack 1)

  • Yogurt + nuts
    • or yogurt + berries
  • Roughly 100–150 kcal

Lunch

  • Veggie soup + protein (meat, fish, egg, tofu, etc.)
  • Small portion of carbs (e.g., one rice ball from a convenience store)
  • When I cook, I eyeball the ingredients and roughly estimate
  • If I buy ready-made or convenience food, I just read the label
  • Rough target: up to ~600 kcal

Around 15:00 (Snack 2)

  • If I feel hungry: a small protein-forward snack
    • Example: a pack of salad chicken (100–150 kcal)
  • If I’m not hungry, I just skip it

Dinner

  • Similar volume to lunch (up to ~600 kcal)
  • After dinner, I basically don’t eat again

→ Most days, this lands me around 1500 kcal in total.

On special days (family meals out, events, etc.), I might easily hit around 2000 kcal.
But since my usual structure is as above, I can adjust by:

  • Skipping the afternoon snack
  • Keeping lunch lighter when I know dinner will be big

So the daily total doesn’t explode.

Why I Prioritize Protein (and a Bit of Fiber)

If you go straight for carb-heavy snacks when you’re hungry
(bread, sweets, etc.), it’s usually:

  • Not great for blood sugar
  • Not great for dieting either

From books and articles I’ve read, and from my own experience, I agree with the idea that:

“A lot of hunger actually comes from protein deficiency,
more than from just low carbs.”

When I eat a small, protein-focused snack, I find:

  • I’m less likely to binge later
  • My focus lasts longer

I also pay some attention to fiber, because:

  • Fiber tends to help satiety hit faster
  • A small handful of nuts, for example, often calms “empty” hunger

So my current pattern is:

  • Snacks are not “treats” but “protein + a bit of fiber”
  • I try to have things like salad chicken, yogurt, and nuts around

How I Treat Eating Out (No Guilt, Just Adjustments)

I don’t want to live in a world where:

“All enjoyable meals must be sacrificed for dieting.”

Family dinners out and meals with friends are, to me, necessary time, not mistakes.

So my approach is:

  • Reduce or skip one of the day’s snacks
  • Add ~10 extra minutes of cardio the next day

Calorie-wise, for me:

  • If I eat ~1000 kcal at a restaurant
  • And keep the rest of the day within my usual pattern
  • My total ends up around 2000 kcal

Given my body size and activity, that’s well within my “allowed” range.
More importantly, not going out just to protect perfect numbers feels like a waste of life.

The Difference Between Athletes and “Regular People”

At some point I found myself asking:

“Why do athletes need that much discipline and sacrifice?”

Take bodybuilders for example:

  • They have clear bulking and cutting phases
  • There is a specific date for competition
  • They must beat their previous self and sometimes others
  • They need numbers to analyze what worked and what didn’t

So they track:

  • Weight
  • Body fat percentage
  • Daily calories
  • PFC (protein/fat/carb) balance

In that world, strict numbers and strict sacrifices have a very rational purpose.

For people like me, it’s different:

  • There’s no competition date
  • There’s no real need for a bulk phase
  • The goal is simply:
    • Stay healthy for as long as possible
    • Move comfortably
    • Avoid getting knocked out by lifestyle diseases if possible

If that’s the goal, then:

  • A short, extreme cut with lots of suffering → not very rational
  • A long-term, low-stress lifestyle you can stick to → much more rational

So my conclusion:

You can stay aware of numbers,
but you don’t have to record everything and feedback daily.

That’s why I ditched the calorie tracking app this time.

From November Onward: Body Fat, Lines, and Rebound-Proofing

Why I Stop Around “Just Above My Ideal Weight”

If you chase the number on the scale too far, you can end up:

  • Very light, but
  • With no real sense of your own body lines

Before diving into harder strength training, I wanted to:

  • Understand where I want muscle
  • See which areas I’d like to trim just a bit more

To do that, I decided:

“I’ll stop once I reach around my ideal weight,
or slightly above it.”

For me, that range is about 63–65kg.

  • I weighed myself on November 1–3
  • The results were 64.0 → 63.5 → 64.0kg
  • So I treated this as “cut complete”

From there, the focus shifts from:

  • “How much weight did I lose?”

to:

  • “What’s my body fat like?”
  • “How do my lines look in the mirror?”
    • Face line
    • Upper back and around the armpits
    • Abdomen

I keep cardio + HIIT roughly as is,
and add in strength training to work on posture, lines, and rebound-resistance.

Body Fat: Current Status and Target (Rough Idea)

I use a normal home-use body composition scale.
So for me, the absolute value isn’t sacred; it’s more about:

“Is this number trending down, flat, or up?”

Right now:

  • As of November 2025: around 17% (roughly stable)

And my rough image of the target is:

  • 16% → 15%, dropping about 1% per month
  • Eventually keeping around 15% as a stable range

Once I actually reach that,
I plan to write a separate follow-up article looking back with more concrete data.

Not Just Aesthetics: Lines & Body Fat for Rebound Prevention

Caring about body fat and body lines is not only about aesthetics.

If you mainly rely on eating less to lose weight:

  • You tend to lose muscle along with fat
  • Your basal metabolic rate drops
  • You end up with a body that regains weight easily when life gets a bit messy

On the other hand, if you:

  • Finish your cut around your ideal weight
  • Then slowly build and maintain muscle while watching body fat and lines

you’re essentially working toward:

“A body that weighs about the same,
but is harder to rebound with.”

That’s why, after reaching my target range, I don’t just say:

“Okay, done. Back to the old lifestyle.”

Instead, I treat this November–onward phase as:

“Building a base that makes it harder to regain fat
even if life inevitably gets a bit imperfect.”

Where This Article Stands (Mid-way Report)

You might be wondering:

“So is this a final success story, or just a plan?”

This article is very intentionally a mid-way report.

It mixes:

  • Things I actually did between July and November 2025
  • Things I plan to do from November onward

To summarize:

  • Weight:
    • 75kg → 69kg → 64kg (all measured)
  • Food:
    • 1500–1800 kcal/day, roughly, without an app (actually doing this)
  • Training:
    • Cardio, HIIT, and simple strength sessions as described above (currently running this plan)
  • Body fat:
    • Around 17% as of November (measured with a home scale)
    • Going forward, I aim to nudge it down to around 15%

Rather than writing a “perfect before/after” with all the hindsight cleaned up,
I wanted to capture the messy middle while I’m still in it.

Also, many people might be satisfied with:

“I got down to my ideal weight, now I’ll just maintain.”

My estimated ideal weight is around 62kg,
so I think my numbers can serve as a rough reference point for people similar to me.

Summary

If I had to summarize this article in one line, it would be:

“A diet that doesn’t throw away numbers,
but doesn’t become a slave to them either.”

Boiled down, the key points are:

  1. Don’t obsess over daily weigh-ins.
    Check at the start, at a mid-point, and after a few months.
    Don’t let water weight decide your mood.

  2. Make cardio weather-proof and chaos-proof.
    Use tools like an indoor bike so your habits don’t depend on sunshine and perfect mornings.

  3. Manage food with frameworks, not exact logs.
    Use a rough daily calorie band and per-meal upper limit instead of strict app logging.

  4. Don’t import athlete logic directly into everyday life.
    Your goal is long-term health and comfort, not stage-ready conditioning.

  5. Stop around your ideal weight, then work on body fat and lines to prevent rebound.
    Think: “build a body that doesn’t immediately spring back up.”

“Crash down and rebound hard”
vs
“Gently reshape things with enjoyable movement and slightly smarter eating over a few months”

I’m aiming firmly for the latter.

If even one part of this article feels copy-and-paste-able into your own life,
I’ll be happy.

And once I’ve spent some time around 15% body fat and seen how stable it feels,
I’ll come back with another update.