It's difficult if you think of it as big, but what if you break it down into smaller, manageable steps? Start by being consciously aware of what you eat in a day (or better yet, week); write it down, do some back of the napkin calorie calculations.

Then adjust. Change one habit; could be reducing portion size by a hundred grams, drinking less, switching to black coffee, I don't know what people have for habits.

Same with exercising, don't go all in at once, try going to the gym or for a long walk once a week. It takes six weeks to stop, change or start a habit, so it will take some self-discipline for that period. But if it's small, incremental change instead of a "change your life around" it's a lot more manageable.

Also be aware of the "survivorship bias", the "before / after" posts on social media, the "I changed my life in $period" - these make it look like it was an overnight lifestyle change, but that's not necessarily true, what you see is the end result and if you pay attention you'll notice that usually there's years between the before / after without any breakdown or in-between progress.