These are 7 solid principles to follow to lose fat provided you are working out. It's not a diet, it's a lifestyle.
Simple version:
Habit 1: Eat every 2-3 hours.
Habit 2: Eat complete, lean protein with each feeding opportunity.
Habit 3: Eat vegetables with each feeding opportunity.
Habit 4: Eat veggies/fruits with any meal. Eat "other carbs" only after exercise.
Habit 5: Eat healthy fats daily.
Habit 6: Don't drink beverages (soda, beer, etc.) with more than 0 calories.
Habit 7: Eat whole foods whenever possible.
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Long Version
1. Eat every 2-3 hours, no matter what. You should eat between 5-8 meals per day.
2. Eat complete (containing all the essential amino acids), lean protein with each meal.
3. Eat fruits and/or vegetables with each food meal.
4. Ensure that your carbohydrate intake comes from fruits and vegetables. Exception: workout and post-workout drinks and meals.
5. Ensure that 25-35% of your energy intake comes from fat, with your fat intake split equally between saturates (e.g. animal fat), monounsaturates (e.g., olive oil), and polyunsaturates (e.g. flax oil, salmon oil).
6. Drink only non-calorie containing beverages, the best choices being water and green tea.
7. Eat mostly whole foods (except workout and post-workout drinks).
Credits to
T-nation article
Sherdog article