You can’t target fat loss in specific areas. The only way to reduce fat is by maintaining a caloric deficit (burning more calories than you consume). Even then, you won’t be able to control which part of your body loses fat first.
If your goal is to get or stay lean, focus on a balanced fitness routine instead of just one exercise.
I believe strengthening your core can help you look slimmer by tightening your stomach muscles and improving your posture.
When I compare pictures of myself slouching versus standing tall with my core engaged, it looks like I’ve lost 30 pounds between the two.
To lose weight, you need a calorie deficit:
Planks are done to build core strength, not for fat loss.
As many have mentioned, fat loss is primarily influenced by your diet. However, that doesn’t mean exercise, including planks, isn’t valuable for other benefits.
What about the shoulders and upper back?
Set goals for yourself and crush them! Start with 30 seconds, or less if necessary, and repeat that 3 or 4 times, gradually increasing the duration. In my opinion, being able to hold a plank for over 2 minutes is impressive.
For as long as you can.
Planks won’t help you lose belly fat beyond the few calories you burn during the minute most people can hold one—similar to skipping a few cookie crumbs.
Building muscle won’t speed up fat loss; only diet will. Focus on r/intermittentfasting.
Also, you can’t target where fat is lost—your body decides that.
*Diet and exercise. You can effectively lose weight by either eating less or exercising more—both create a calorie deficit. However, I would emphasize exercise over diet for benefits such as increased muscle mass, improved bone density, and lower blood pressure and resting heart rate. Reducing empty calories is beneficial, but I’ve seen many people who diet end up developing an eating disorder.