A healthy and fit body has a high ratio of lean mass to fat. Lean mass refers to all the components of your body that aren't fat, including muscle, bones, organs and connective tissue. Lean mass requires more energy for your body to sustain than fat, so it also offers a metabolic boost -- making weight management easier. Muscle, particularly, provides you with strength and stamina, while excess fat only puts you at increased risk of disease. A lean body mass diet helps you maintain, and even build muscle while losing fat. Exercise should be a critical part of your plan, along with quality, nutritious food.
Lean Mass Makeup
Measures of lean mass are usually shown as a percentage of body fat -- not lean mass. For example, the average woman has a body fat level of 25 to 31 percent and an average man, 18 to 24 percent. To determine your lean body mass, simply subtract your body fat percentage from 100. So, in this case the average woman has 69 to 75 percent lean mass and the average man has 76 to 82 percent.
When you're fit, your body fat is even lower -- with women from 21 to 24 percent fat and men from 14 to 17 percent. Athletes and committed fitness enthusiasts usually boast body fat levels of 14 to 20 percent for a woman and 6 to 13 percent for a man. On the other extreme, women with body fat more than 32 percent and men with more than 25 percent are considered obese. No absolute standards for body fat exist, so each health and fitness organization bases the ranges of body fat on slightly different markers, such as age and health risk. The definition of "healthy" or "athletic" body fat varies slightly, depending on the organization you consult.
To achieve a lower body fat percentage, you need to build muscle or lose fat, or both. Just 10 weeks of resistance training can help you reduce fat by 4 pounds and increase muscle by 3 pounds, as indicated by Current Sports Medicine Reports in 2012. Resistance training can also produce improvements in bone density that can be 1 to 3 percent. Without exercise, you experience a loss of 3 to 8 percent of your muscle mass per decade after age 30, as a natural result of aging.
Design a Diet for Lean Mass
Your goals dictate how stringent your lean body mass diet will be. If you're looking to reduce fat from obese to average, you'll see benefits from adding a little extra exercise and cutting back on sweets, especially soda. If you're already lean, but want to achieve an athletic body fat, follow stricter exercise and eating strategies. The leaner you hope to get, the more changes you'll need to make in your lifestyle.
Building muscle while losing fat is a slow process. A mild calorie deficit that promotes a loss of 0.7 percent of your body weight weekly is more effective in increasing body mass and reducing fat weight, compared to a loss of 1.4 percent body weight weekly, according to a study in a 2012 issue of International Journal of Sport Nutrition and Exercise Metabolism. So, for example, a 150-pound person would be better off losing only 1 pound per week instead of 2 pounds, if she wanted to build lean body mass while dropping body fat.
A healthy, portion-controlled diet can help you achieve the calorie deficit necessary to lose fat. A pound of fat equals 3,500 calories, so to lose 1 pound a week, you must create a calorie deficit of 500 calories per day.
Dietary Efforts to Build Muscle and Lose Fat
Include ample protein at meals to prevent a loss of lean mass as you cut calories. An intake of 0.6 to 0.8 grams per pound of body weight per day helps offset lean muscle mass loss, concluded a review published in Sports Medicine in 2014. For a 175-pound person, this ranges from 105 to 140 grams per day. Good sources of protein include eggs, low-fat dairy, lean steak, white-meat poultry and fish. An egg, for example, contains 6 grams of protein, 3 ounces of lean steak contains 23 grams, and 1 cup of chopped, roasted chicken contains 41 grams.
Exactly how much protein you need per day depends on your goals, your fitness level and the intensity and frequency of your workouts. A dietitian or trained fitness professional can help you determine the exact intake that's right for you.
Whole Foods to Eat With Protein
In addition to lean protein, foods such as watery, fibrous vegetables, fresh fruit, whole grains and unsaturated fats are necessary to support fat loss. These foods are a source of carbohydrates, which you need to support energy. Examples of appropriate meals include: scrambled eggs with spinach and tomatoes alongside a banana; a turkey sandwich with lettuce and tomato on a whole-grain pita with low-fat yogurt; and roasted salmon with brown rice and steamed broccoli. Serving sizes depend on your exact calorie needs and protein-intake goals.
Snacks might be a tangerine with a handful of raw almonds, cut-up vegetables with hummus or cottage cheese combined with blueberries. A protein-rich snack along with some carbs, such as Greek yogurt with berries or canned tuna with whole grain crackers, should be consumed right after your training session to help with muscle growth and repair.
Exercising to Create a Lean Body
Weight loss on the scale doesn't always mean you're improving your ratio of lean tissue to fat. Attempt to lose weight without exercise, and a quarter of every pound you lose comes from valuable muscle. Weight training is a must when your intention is to create a leaner frame. Use a weight that feels challenging by the last two to three repetitions, gradually adding another set or two of each exercise and more weight each week. Work up to three or even four workouts per week, but leave at least 48 hours between specific muscle groups trained.
Also include cardio exercise, working up to 150 minutes of moderate-intensity exercise, as recommended by the Centers for Disease Control and Prevention. consider adding in high-intensity interval training, or HIIT, which involves alternating bursts of high-intensity and low-intensity work -- sprinting, then walking, for example.