I am almost 50. I have been a "Gym Rat" since I played ball in High School. I have done a bit of everything except surgery.
The older you get. The Harder it will be to lose weight and maintain a nice physique... MUCH harder! But it can be done and I have maintained a good physique for my age no question. How do I know? Well... I am my own biggest critic. My lovely wife would NOT have it any other way. And when people mistake me for being in my mid 30s regularly, I know I am doing something right.
To answer your question:
Your calorie intake MUST be reduced and or burn more than you consume.
Intermediate Fasting is VERY effective: For me, little to no Dinner is effective.
Eliminate SUGAR!!! Limit simple carbs like bread, potato, rice, pasta to morning or afternoon meals: Do NOT eat them after 2pm.
A combination of Strength Training and Cardio is a must.
Above all else... DISCIPLINE to follow the above.