How to Lose 40 Pounds in 3 Months

You've got just three months to slim down to look your best for that wedding, vacation or reunion. Losing 40 pounds in three months is your goal, and you're dedicated to achieving it. A low-calorie, highly nutritious eating plan combined with increased physical activity brings about weight loss. Losing the more than 3 pounds per week required to lose the 40 pounds by your deadline may be a little aggressive, though. You can make serious inroads into weight loss so that you feel and look better in the three months, even if it takes you longer to reach your 40-pound weight loss goal.

Woman weighing herself on scale (Image: Assembly/Photodisc/Getty Images)

Be Realistic About Your Weight-Loss Goal

Most major health organizations recommend you lose up to 2 pounds per week. Losing weight too quickly usually requires an unsustainably low calorie intake level. You may find yourself feeling exceptionally deprived, leading to frustration and abandonment of your goal. You might also develop nutritional deficiencies if you trim calories too much.

Eating fewer than 1,200 calories per day as a woman, or 1,800 as a man, tends to slow your metabolism as your body compensates for what it perceives as starvation. Eating too few calories may also cause your body to burn lean muscle mass, especially if you don't exercise. When you lose muscle, which requires more energy for your body to sustain when compared to fat, your metabolism drops further and weight loss becomes even harder to achieve.

The three months allows you to safely lose 24 pounds, and maybe as much as 30 pounds. You may lose more than 2 pounds per week in the first couple of weeks, because diet and exercise lifestyle habits cause you to drop extra water weight in the first few weeks.

Manage Calories to Lose 40 Pounds

To lose 2 pounds per week, you'll need to eat about 1,000 calories fewer than you burn. Determine your average daily burn rate by using an online calculator that accounts for your age, gender, activity level and size. Subtract 1,000 calories from this number to determine the number of calories you should consume to lose the safe, sustainable 2 pounds per week. If this puts you at calorie intake below 1,200 for a woman or 1,800 for a man, cut calories less severely and move more.

To lose the 3.3 pounds per week you'd need to reach your 40-pound weight loss goal, you'd have to make this deficit equal to 1,650 calories. Very few people can achieve that deficit and still take in the necessary calories for good health and feel energized. Also know that losing more than 3 pounds per week consistently can cause gallstones, too.

Eat Wisely to Lose 40 Pounds

Design meals to include mostly lean proteins and generous amounts of fresh fruits and vegetables. At least 0.55 grams of protein per pound of body weight per day helps with feelings of satisfaction and prevents the loss of lean muscle. This means a 200-pound person's protein goal is 110 grams daily; that's about 30 grams at each meal and 10 to 15 grams at each of two snacks. For reference, an egg contains 6 grams of protein and 72 calories; a 3-ounce serving of turkey breast contains 25 grams of protein and 125 calories; and a 3-ounce broiled lean ground beef patty contains 22 grams of protein and 155 calories.

Include whole grains, low-fat dairy and unsaturated fats at one or two meals daily too, so you don't miss out on essential nutrients. Abandon processed foods, like fast foods and sweets, and, instead, go for foods with nutrients your body really needs. Examples of quality meals include eggs scrambled with spinach next to a whole-wheat English muffin; oatmeal with berries, walnuts and almond milk; grilled chicken with quinoa and broccoli; broiled tilapia with steamed spinach and brown rice; or lean flank steak over a large salad. Exact serving sizes depend on your personal calorie needs.

Avoid skipping meals to save calories; it only leaves you ravenous later, so you end up bingeing or making less-than-optimal choices.

Adopt an Active Lifestyle

The more active you are, the greater your daily calorie burn. This helps you lose weight more quickly, and will help preserve lean muscle as you shrink. If you don't exercise while you lose weight, especially at a relatively aggressive rate, one-quarter of every pound you lose will come from lean muscle mass.

Work up to a minimum of 150 minutes of moderate-intensity cardio weekly, which includes brisk walking or water aerobics. Once this is doable, strive for as much as 250 minutes per week to lose significant weight, suggests the American College of Sports Medicine. Perform a few of these workouts at a higher-intensity to boost your calorie burn even more.

Strength train at least two times per week as well to maintain and build lean muscle. Not only will you look more fit and toned when you lose the 40 pounds, but you'll create more of the tissue that helps boost your metabolism. Aim to work every major muscle group with at least one exercise at two workouts per week. Resistance bands, free weights and machines are all acceptable tools for such training. Consider consulting a fitness professional to help design a program for your needs.

Move more every day too; these extra calories add up to help increase your calorie deficit. Park far out in the lot, choose the stairs instead of the elevator, take the dog for an extra walk, or play catch with your kids.