The Basal Metabolic Rate (BMR) is determined by age, gender, height and weight, as well as individual genetic factors. It solely covers the basal processes of the body and nothing on top of it - not even walking. As you can see, your age is only one factor in determining why your metabolism runs the way it does. Some people talk of having a "slow" or "fast" metabolism. In reality, your basal/resting metabolic rate can fall anywhere from low to high. However, your rate is what's normal for you and refers to how many calories you use just for breathing, digesting your meals, etc. Those functions make up about 75 percent of your daily energy, or calorie use, and you can't influence them very much. Physical activity comprises the rest. In fact, physical activity and building lean muscle mass is what truly contributes in sustaining or even elevating your metabolic rate. Yes, as you may have heard, as you get older, your body's metabolism slows down. Think of it like a car's engine. The food you eat (fuel) gets turned into energy, which is used to run your bodily activities. With age, that process begins to operate less rapidly than it did when you were an infant. While your metabolism stabilizes somewhat between the ages of 20 and 40, it then tends to go down as you continue to age.
Whenever you lose weight, whether intentionally or not, your BMR goes down. Although the pounds will dwindle, so will your metabolic rate and most likely your lean body mass — which you don't want. By going on a crash diet, you will have a hard time getting the nutrients you need. Without the daily requirement of protein, your body will break down your lean muscle mass. The body does a good job in making sure it gets what it needs to function — and if it doesn't get what it needs from food, it will take protein from the muscles to make cells. In essence, your body will eat away at your own muscle mass, which means less lean muscle mass and therefore, burn fewer calories. Although, crash dieters may lose 10 to 20 pounds, they are likely to gain it back because they have lowered their metabolic rate and their approaches to losing weight are not sustainable. Unfortunately, when they gain the weight back, it does not store as muscle but as fat instead. Fortunately, there's still good news! Your BMR is not permanently damaged no matter how many yo-yo diets you have been on in your life. However, a good way to prevent yourself in becoming a yo-yo dieter is to always strive to build muscle and stay active in general and find a measured approach to healthy eating.
In our early 20's, the bones and muscles tend to be thriving as they continue to grow, which means the metabolic rate is at its prime. This then changes, even though their nutrition has changed, their bodies have. This is because after the age of 25 — which is the age where we stop growing bone — the metabolic rate goes down by 2 percent or more per decade. So, in order to stay at the same weight without a change to your level of activity, you would have to cut your daily calories by the same amount
In your 30's, you start to experience gradual bone and muscle loss. Due to these reasons, this can slow down your metabolism and may cause weight gain, especially if you are not keeping active with exercise or make healthier eating choices. This is also a decade when many woman start having babies. Unfortunately, sometimes shredding off the weight post pregnancy can be a little challenging but surely can still happen, with exercise and healthy eating practices. Weight training with cardio exercises, in this decade is most important. In addition to this decade, hormones begin to change as well as your fertility does, which causes mood swings, anxiety, sleep disturbances, and hot flashes.
In turning 40, this milestone age has been known to cause our metabolisms to slow down, resulting in seemingly unexplainable weight gain. This is because, at the age of 40 and on, estrogen levels drop, which causes insulin levels to go up and thyroid levels to go down, both of which increase hunger. You wind up eating more and burning fewer calories. Also, at the age of 40 some studies suggest that it is even possible that women may lose muscle mass twice as fast as men. Moreover, in this decade, we tend to lose the most muscle mass on the body's largest surface areas like the core muscles supporting your shoulders and belly, as well as your thighs. Indeed, after 40, your metabolism winds down 5% every 10 years thereafter, which means you need to really focus and continue to make healthier food choices and consume fewer calories and continue to exercise doing a combination of aerobic and resistance training.
Starting at the age of 30, most people begin to lose about half a pound of the metabolism-revving tissue each year. Poof! Gone, just like that. And at age 50, the rate tends to double. Hormones may continue to decrease which further causes insulin to decrease and thyroid to increase. It has been said that the average sedentary woman may have lost nearly 15 pounds of muscle by the time she reaches her late 50s, a change that could cause her to gain nearly the same amount in body fat. However, if the same woman was active with resistance training, the outcome would be different. That being said, if you have been sedentary, now is the time to make a healthy change and start to include regular exercise into your routine. Remember exercise doesn't only help with your muscles and metabolism but also with hormone balance, enhances bone health, and decreases your risk in developing unwanted chronic conditions.
Decreased muscle tone and metabolism may become obvious until after the age of 50 and more so at the age of 60 and on. This occurs because the basal or resting metabolic rate continues to decrease leading to weight gain, slowed digestion and low energy levels. The reason is that there are declines in the number of cells in each organ that reduce metabolic rates. Muscle fibers and muscle fiber size also continues to declines and results in a decreased amount of muscle mass. In turn, this declines the cardiac output and oxygen volume, which results in lowered cardiovascular endurance. As you can see, it is so important to remain active at any age to slow down the progression of these natural processes that our body tends to endure. Other than keeping active, remember to eat breakfast within one hour of waking up, eat small but frequent meals throughout the day, add a source of protein in every meal and remember to take Vitamin D and B complex vitamins to increase your energy needs.
Your Nutritionist and Coach,