What to efter 60 yrs

In general, losing weight in a function of consuming fewer calories than you expend. How you do this is up to you. There is no magic food, size/number of meals, or anything else that works long term for weight loss. Just eat less than you burn to lose weight. To be healthy, eat a nutritious diet and move more.

I would suggest that after sixty it is even more important to "eat healthy" than when we were younger. We have more likelihood of developing diseases and syndromes that are exacerbated by poor nutrition as we age. I have a few months left in my sixties. I am working my way toward a lower weight and regular exercise. I am keeping an eye on sodium and my blood pressure. I am trying to control Type II diabetes so take my meds and try to stay within limits on carbohydrates. Those things may not be at issue for you.

To start to learn about nutrition, look at Nutrition Source's "Healthy Eating Plate" and linked pages on the site. https://www.hsph.harvard.edu/nutritionsource/