The human body is made up of fat, lean tissue (muscles and organs), bones, and water. After age 30 our bodies slowly begin the process of atrophy–the loss of lean tissue—where our muscles, liver, kidney, and other organs may lose some of their cells. We lose lean tissue and take on body fat. In fact, older people tend to have one-third more fat than they had when they were young. A big reason is that less dense fat replaces lean muscle tissue. Being overweight can be unpleasant, uncomfortable and unhealthy and it makes us want to lose weight, but is it weight loss or fat loss we are really after?
Weight loss is defined as a decrease in overall body weight from muscle, water, and fat loss.
Fat loss refers to weight loss from fat, and it's actually a more targeted and healthy goal than general weight loss.
Studies show that men generally tend to gain weight until about age 55 and then begin the process of weight loss later in life caused by a drop in the male sex hormone testosterone.
Women generally tend to gain weight until about age 65 and begin to lose weight thereafter. A great deal of this excess weight for women tends to localize in the girth around the internal organs and, unfortunately, this is mostly fat. Hormonal and lifestyle changes are often the cause of weight gain but not always.
Our goal in weight loss should be maximum lipolysis which makes way for lean body mass. Lipolysis is the biological process of breaking down fat lipids and triglycerides in the food we consume, and which is already stored in our bodies. This process largely occurs in the mitochondria(1) of the muscles which is why the more muscle we have, the more fat we burn. Exercise helps regulate lipolytic enzymes and improve mitochondria function and this is why strength training or other vigorous exercise helps us with fat loss. (Be sure to check out our previous blog, “Exercise and Stretching: Simple Remedies for Cellulite and Fatigue” here. This article discusses the kind of workout routine that burns fat while building lean muscle tissue.)
Losing fat and increasing lean body mass is healthiest when it comes to weight loss. While we can afford to lose fat, we can’t often afford to lose lean body mass or muscle.
“A smaller lean body mass may mean that many older people lack the physical reserve to withstand a prolonged period of critical illness, where more than 1% of body protein may be lost each day even when adequate energy and protein are being provided.” — Nancy Bernhardt et al in "Nutrition for the Middle Aged and Elderly”
Physical training, no matter our age, has proven very positive for increasing lean body mass even in the very elderly.
Losing the fluff of fat and gaining muscle firmness and tone will create in you the kind of leanness that makes for a strong, toned better-proportioned body that is able to meet the physical challenges of daily life.
In addition, once your muscle mass begins to increase while fat decreases, you’ll notice you have the greatest prize of all–more energy.
Lean body mass is also important for:
Respiratory muscle strength
Improved circulation of blood to the organs which keeps them healthy and able to rid the body of toxins
The ability to fight diabetes because muscles store glycogen for a readily available energy source when needed
Improved bone strength and density; although exercise targets muscles it also strengthens the bones because bones, like muscles, react to the demands we place on them.
Muscle loss often happens when we focus solely on calorie restriction for weight loss. Restricting calories usually involves macronutrient restriction. Without enough protein in the diet, the body cannot rebuild lean body mass even if we’re strength training. Also, the amount of lean body mass we carry directly impacts our metabolism. Less muscle causes a lower basal metabolic rate (BMR)(2) which translates to a lower calorie burn throughout the day. This demonstrates the symbiotic relationship between lean body mass and a greater ability to burn calories from fat.
But even given our health goals of fat loss, we need to keep in mind that it’s actually important to carry some body fat.
”Fat helps give your body energy, protects your organs, supports cell growth, keeps cholesterol and blood pressure under control, and helps your body absorb vital nutrients. When you focus too much on cutting out all fat, you can actually deprive your body of what it needs most.” — Harvard Health Publishing
It’s relatively easy to know when we’re carrying too much body fat but the Body Mass Index (BMI) is a more specific indicator of how much fat we carry and if that fat is within a healthy range. The BMI is calculated by taking your weight in pounds and dividing that number of pounds by the square of your height in feet.
A high BMI can indicate high body fatness. BMI screens for weight categories that may lead to health problems, but it does not diagnose the body fatness or health of an individual.
To easily calculate your BMI, go to this link provided by the National Institute of Health and enter your height and weight inside the purple-framed chart. Then refer to the left column highlighted in yellow to determine which BMI category you fall in.
Our body shape and weight change naturally as we age, especially if we make no lifestyle changes. Understanding the difference between mere weight loss and fat loss is important for our health, vitality and quality longevity.
Just maintaining a thin body created by general weight loss without attention to muscle tissue maintenance or building is no longer proven to extend longevity as was once believed. It’s more so lean body mass created by a combination of fat loss and exercise that gives us the ability to undertake daily activities with confidence and to mitigate and slow the aging process.
(1) an organelle found in large numbers in most cells, in which the biochemical processes of respiration and energy production occur. It has a double membrane; the inner layer being folded inward to form layers (cristae)
(2) the rate at which the body uses energy while at rest to keep vital functions going, such as breathing and keeping warm.
“Calculate Your BMI - Standard BMI Calculator.” National Heart Lung and Blood Institute, U.S. Department of Health and Human Services, https://www.nhlbi.nih.gov/health/educational/lose_wt/BMI/bmicalc.htm.
“Know the Facts about Fats.” Harvard Health, 19 Apr. 2021, https://www.health.harvard.edu/staying-healthy/know-the-facts-about-fats.
Tallis, Raymond, et al. Brocklehurst's Textbook of Geriatric Medicine. Churchill Livingstone, 2003.
Bernhardt, Nancy E., and Artur M. Kasko. Nutrition for the Middle Aged and Elderly. Nova Science, 2008.
Fogelholm, Mikael. Physical Activity: A Part of Healthy Eating?: Report from a Nordic Seminar, Lahti, Finland, February 2000. Nordic Council of Ministers, 2001.
TodayShow. “Can Exercise Detox Your Body? It's Not about the Sweat.” TODAY.com, 17 Dec. 2012, www.today.com/health/can-exercise-detox-your-body-its-not-about-sweat-1C7634616.