I've been vegetarian for 6 or 7 years.... No meat, a normal amount of carbs
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Yes, portion control and activity are the way to go.
When I was cutting weight to enlist, I counted my calories almost obsessively. I had a set amount that I would not go over each day. It wasn't ridiculously low or anything, but a limit was set and I stuck to it.
To prove a point to a friend who felt fad diets where the way to go, I spent a week getting my calories from junk food. No surprise, I lost weight at the end of that week. I just kept my calories to where they were supposed to be and kept up my activity level.
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While I personally would not go meat free, it just illustrates that a lot of different things can work.
The truth is, it is a simple math problem. I tried every fad diet there is, including Atkins (which actually lead to blood pressure and cholesterol increase).
But as I was saying, it is a math problem. Calories in < calories used for your activity and body weight. After years and years of trying different diets, it came down to the simple fact that I had to reduce calories.
Finally, after years of trying, I was able to lose 45 pounds. I still have some to go, but I'm on my way.
Like Ski mentioned, I eat anything. Meat, pasta, rice, fish, vegetables, fruit, and even cake, pie, candy, ice cream.....
I just make sure I keep the calories down, and you don't deprive yourself of anything.