The basal metabolic rate, or BMR, is the rate at which we burn calories while at rest. Simply put, BMR is a measure of the energy expended by the body to breathe, digest food, circulate oxygen in the blood, and other such essential survival functions that the body carries out on its own.
Most people believe bodyweight is the single most important marker of health, but it’s actually the rate at which we burn calories that determines the state of our health. Though the actual calculation of BMR is complicated, involving medical monitoring and ideal test settings, a simple approximation for ideal BMR can be derived from this equation: Bodyweight (in kg) multiplied by 24 for men, and bodyweight multiplied by 23 for women. This can then be compared to an actual reading of a person’s BMR in test conditions.
Weighty issues: Excess weight alone is not responsible for health problems.
Many normal-weight persons may have unhealthy levels of fat when body fat percentage is measured clinically. Or you could be a heavyweight person, but with a healthy body fat percentage. This is because the same volume of lean muscle weighs more than fat. Also, muscle tissue, unlike fat, contains a multitude of blood vessels, which in turn increases the supply of oxygen, the use of energy and the BMR. BMR is a great indicator of lean muscle vs body fat, because lean muscle mass escalates BMR, while fat makes it sluggish.
Anyone who has 30% body fat is obese, irrespective of weight. For males, on an average, 15% of the total bodyweight comes from fat; the figure is 20% for women, according to the American Diabetes Association.
Take, for instance, the case of a young woman in her 30s who is 5 ft 4 inches and sports a so-called healthy weight of 59kg in accordance with her height. Her mirror image is pleasant, thin, and her frame small. Her body composition, however, tells a different tale. She has an unhealthy 32% body fat (obese), and her light weight and slim frame are the result of weak, lightweight bones and low muscle mass. Because of the excess fat her BMR is sluggish—instead of the ideal 1,357 calories, it reads 1,200 calories.
A typical diet for such a person would include foods that are low in fibre and protein and quick to digest, meals after a long gap of 4-5 hours, and a large helping of junk food to keep hunger pangs at bay. She would also have no energy to exercise.
Low-fibre, high-starch and protein-deficient meals and long gaps between meals slow the BMR, and even if such a person appears to maintain weight, he or she accumulates body fat and becomes obese over time. Low BMRs can also lessen immunity, change body shape to apple or pear, lead to osteoporosis, fatigue, listlessness, low energy, and disturbed menstrual cycles.
Some suggestions to increase BMR:
• Reduce the long gaps between meals. Gaps of more than 3-3.5 hours make the body conserve energy in response and slow down the metabolic rate till there is more energy in the form of food.
• Make breakfast wholesome. Oats with skimmed milk, one apple, some ground flaxseeds and cinnamon are a healthy option because they are high in fibre and complex carbs, and the body has to work harder to digest them, thus pushing up BMR. Oats, apple and flax are high in fibre, skimmed milk is rich in calcium and protein, cinnamon helps to balance blood sugar. Flaxseeds are also a high-fibre food rich in omega nutrition.
• Lunch and dinner must be 3-3.5 hours after the previous meal and include 1 cup of multicoloured vegetables, dark green salad, some skimmed cottage cheese, chicken or fish, one high-fibre carbohydrate option like brown rice or multigrain roti and a cup of skimmed yogurt. Adequate protein nutrition increases BMR. Protein provides amino acids for muscle growth and for the repair and restoration of body organs.
• An evening snack is a must and could include a protein-rich serving of sprouts with yogurt or fruits with a handful of peanuts or, better still, a skimmed cottage cheese, chicken or tuna salad. Nuts and seeds contain healthy fats that increase the BMR.
• Around 30-40 minutes of exercise daily in the presence of adequate nutrition also goes a long way in improving BMR by using up additional fat calories and increasing muscle tissue. Weight training is especially useful because it increases lean muscle mass and, therefore, BMR.
Madhuri Ruia is a nutritionist and Pilates expert. She runs InteGym in Mumbai, which advocates workouts with healthy diets.
Write to Madhuri at email@example.com