Walking isn't the only form of exercise.
Rope skip, swimming, hit the gym, use the stairs more.

Stop saying weather too hot! can't walk!
We are lucky, can buy cars and drive everywhere!

Eat wisely. Drink water.
Avoid sugar, carbs like rice/noodles, salt when possible.
Or at least ask for less sugar when you buy drinks and eat less rice every meal.

Our diet is full of sugar, salt, and all kinds of condiments.
Original taste of food totally disappear under sauces, spices, thick gravy.
And we keep telling ourselves- Malaysia food sedap! delicious! yummy!
Our food is the best! Other people's food taste like sh*t!

Comparing with SG is pointless.
It's an urbanised city with good public transport with good network with trains and buses. Cars are not necessary.
They have underpasses, pedestrian-friendly pavements and sheltered walkways everywhere.
Plus their government and people are exercise crazy. They have apps which reward you for exercising/walking. Their parks and gyms are well-utilised. Their hawker stalls have sticker reminders: less salt, less sugar, more vegetables.
Take a walk in the evenings there and you will realise tons of their people are jogging and strolling.

Our overweight/obesity rates are at 53.5%. No. 1 in Southeast Asia.
Obesity is linked to cardiovascular diseases, diabetes, musculoskeletal disorders and cancers.
Our diabetic patients are shooting through the roof.
Hypertension is prevalent in 49.93% of adult Malaysians.

All these combined to become a very serious problem in Malaysia.