If it works for you, great. My diet is totally opposite of yours, but it's been working well for me for the last year. It's more of a paleo-style diet- no grains or processed foods, a wide variety of veggies, meat/poultry/fish/eggs, nuts, occasional fruit, coconut oil and olive oil. Over the last year, my calorie intake has been ~50% fats, 30% protein and 20% carbs.
I've tracked my food intake using an account at Fitday.com, which shows me calorie totals and nutrient levels. I can see which nutrients I'm getting enough of, and which I'm lacking. Calcium, magnesium and potassium are three I have a hard time reaching the RDA of, but I take a multivitamin daily.
Over the last year I've lost 90 pounds. The last couple months I've been averaging from 1200-1400 calories most days. When I get hungry I eat, usually small meals of around 200-300 calories. Every 2 or 3 weeks, I'll feel the need to gorge and have a day of around 3000 calories.
A few years ago I tried eating a diet that counted on beans and rice as the main staples, and for me, hunger was always there. With the diet I'm eating now, sometimes I worry that I'm not getting enough calories, since I rarely have hunger pangs. I have a theory that the reason for that is that I'm careful about getting complete nutrition, even when total calories are low, and that hunger isn't completely caused by a need for calories, but also a need for nutrients.
And I'm sure my food costs more than yours, but I buy as cheaply as possible, always looking for sales and the best prices. I spend around $300 per month on food just for myself.