If you want to lose 7 lbs. in a month, there's good news and bad news: it's possible, but you may find it difficult to lose all that weight and keep it off after the month is up. You'll almost certainly need to utilize a combination of diet and exercise to lose 7 lbs. in a month; you'll need to burn or not consume 3,500 extra calories for each pound you want to lose, so that's 24,500 calories for the 7 lbs. you want to lose.
Determine how many calories you normally consume in one day, and reduce that number by 500 calories to lose 1 lb. pound every week -- enough to lose 4 of your 7 lbs. in a month. Use a food journal or an online calorie counter to track your calories.
Substitute healthy foods such as fruit, vegetables and whole grains for chips and fast food, and skip high-fat, sugary desserts. Simply cutting calories will help you to lose weight, but if you want to sustain your weight loss, you'll need to improve your eating habits.
Exercise frequently -- as often as once each day if you can manage it. According to Harvard Medical School, walking at a moderate pace burns about 300 calories an hour for a person who weighs 150 lbs. To lose the rest of the 7 lbs., walk for about one hour each day.