Breakfast is exactly what it is - break fast - the first meal of your day.
Just because many eat breakfast in the morning, that does not mean everyone does. Lunch is the first meal of the day I eat, so for me, it is breakfast.
Some days I eat eggs, others I eat a piece of grilled fish or a steak. What is the most important thing is to understand that if you eat something for your first meal of the day that spikes your insulin levels, you will spend the rest of the day lurching from blood sugar high to blood sugar low. Protein does not spike blood sugar and means you're less likely to have a sugar crash and reach for something sugary as a quick pick me up. I also eat my biggest meal for breakfast, and lightest for dinner, although if I am going out to eat, this might not be the case!
I suggest reading the Glucose Revolution. Lots of helpful tips in there.
Am not going to push for to exercise, I know from my own experience (as well as talking to others) that it's diet and what you eat that's key. I do intermittent fast in as much as I eat between 12:00pm-6:00pm, but I find that having a cut off time means I won't mindlessly snack on the sofa watching the tv in the evenings.
Your waistline thickening is absolutely to do with perimenopause. The fat that accumulates here produces oestrogen which is why in our 40s, this is where women tend to gain weight. I know that my waist did start to thicken, but it's back to what it was pre-menopause now. But, it was hard work and the last place the weight came off. It's also the first place weight goes if I so much as look at a piece of cake.
Good luck with everything.