Michelle, if one limits calories, and the carbs are low enough, yes, one can be in ketosis. I can't imagine that 1500 calories made up of carbs would mean ketosis, unless one runs marathons or races dog sleds, etc. ;)

Starvation mode comes from not getting enough nutrients, especially not getting enough meat and meat fat.

1500 calories is not a low level of caloric intake, according to the USDA surveys of years gone by.

What makes up those calorie is crucial. Meat, meat fat, and veggies must by the mainstay in order to get nutrients. I make sure I get at least 50 grams of protein from meat, each day. I eat between 50-75g/PROd. An easy standard is that one ounce of cooked meat is 6-7 grams of PRO. A large egg is 6g of PRO. Beef fat and butter for nutrients and cell regeneration, and feeling well. A few plants for micronutrients and variety.

If it interests you, have a look at the Food Surveys at the USDA site:

.usda.gov/Services/docs.htm?docid=16180

The standard amount of calories for women, for decades was 1500. Women who did hard, physical work on farms ate more.

For older women, that amount is often markedly fewer calories. At 20-30g/CHO/d, 1500 calories barely keeps me maintaining. I maintain more easily at 1400-1450 calories per day. To lose weight, my daily average must be under 1200. I don't plan the calorie cycling, it just naturally occurs. Some times I eat more, some days less.

Age, genetic makeup, diet and health history, blood sugar regulation, insulin response, lifestyle, stress responses, food plan, supplements, etc. all figure in dramatically.

If it appeals to you, there is much help and support for ladies doing carb and calorie cycling, limiting, and all sorts of plans, at Low Carb Friends, and Active Low-Carber Forums. Low Carb Friends is especially friendly, and almost completely free of young men making pronouncements about what other people ought to do.

Hope this helps!

All the best to you. :)