April 05, 2022

Why Your Body Is Changing Even If Your Diet and Exercise Aren’t

Written By

Allie Baker

Medically Reviewed By

Vinita Tandon, MD

Lifeforce Medical Director

Does this sound familiar: You’re working out regularly. You’re eating clean. You’re caring for and nourishing your body. Nothing in your wellness routine has changed — but your body has. 

As you age, you may notice you’re feeling less lean, strong, and toned as you have in the past, and your stamina might be lagging, too. “When we get older, we lose lean muscle mass and hang on to more body fat,” says Dr. Vinita Tandon, Lifeforce’s Medical Director and a board certified endocrinologist. “The things you used to do to stay in shape may not work as effectively as they did before.” 

Research shows that when comparing people who are under 40 and over 40, muscle mass and strength can decline anywhere from 17% to 41%. 

So what do you do? Make adjustments and keep adapting. 

Why Your Body Is Changing

It’s tempting to just throw up your hands and say, “Oh well, I can’t help that my body is changing.” While change is constant, you do control how you respond to it. Knowledge is power, so it’s helpful to know the why behind the changes. There are several physiological reasons your weight may be going up and your lean muscle mass going down — even if your diet and exercise routine remain status quo.

Hormone Fluctuations

We talk a lot about hormones here at Lifeforce because they impact so many systems in our bodies, how we feel, and yes, how we look. Hormones play a huge role in changing body composition, says Dr. Tandon. “If you don’t have optimized hormone levels, you can put in the work with exercise and diet but you won’t get the results you’re looking for.”

You might already know that men’s testosterone levels peak at age 30 and begin to decline 1% to 2% every year after that. But women, too, see a big drop in testosterone during perimenopause, usually in their early to mid-40s, according to Dr. Tandon. Starting in middle age, you also have less DHEA, an adrenal hormone that is a precursor to testosterone. “When you lose those hormones, you start to lose lean muscle mass,” she says.  

Research shows that men with low testosterone levels experienced more muscle loss and increased fat mass with age. Dr. Tandon says this applies to women as well. Lean muscle mass helps determine your resting metabolic heart rate (RMR), the number of calories your body burns at rest, so it impacts your metabolism. 

Testosterone and DHEA are also key for muscle recovery. “As they get older, people will say, ‘I did a tough workout and it took me a week to bounce back,’” says Dr. Tandon. “Optimizing those hormones will shorten recovery time so you can train more often.” 

Thyroid hormone is another one to watch. “We have a thyroid hormone receptor in almost every cell in our body and it impacts stamina, endurance, and energy,” says Dr. Tandon. “Thyroid hormone declines with age, and this is often an underdiagnosed condition. If you have unexplained weight gain, that’s one of the first things you should check.” And it’s one of many biomarkers measured in the Lifeforce Diagnostic.

Another underdiagnosed imbalance is human growth hormone, which plays a key role in lean muscle mass, strength, and stamina. “It can be quite low when you enter your 40s, 50s, and onward,” notes Dr. Tandon. “Boosting growth hormone can really help tip the balance to see better results.” 

Why Your Body Is Changing Even If Your Diet and Exercise Aren’t

Nutrient Absorption 

“As we get older, our bodies are less efficient at processing vitamins and other nutrients,” says Dr. Tandon. For example, we absorb less vitamin D, which is “important for overall body composition,” she says. Vitamin D plays a key role in cellular pathways related to energy, stamina, and endurance, which affect our ability to build muscle through exercise. Not to mention, vitamin D plays a major role in bone health, which is linked to how much we can squat, bench, or carry from the car to our front door.  

Sleep Changes

It’s not just you — the quality of our sleep often deteriorates with age, says Dr. Tandon. Our bodies naturally produce less melatonin, a hormone that regulates the sleep-wake cycle, and the cells in our hypothalamus, which controls sleep, are less efficient in regulating our circadian rhythms. (For more on why you’re losing sleep as you age, read this.) 

“Sleep is really important for muscle recovery,” says Dr. Tandon. “If we don’t get quality deep sleep, our muscles don't recover and we can’t build new ones.” Research shows that people who didn’t get enough rest had decreased protein synthesis, resulting in the loss of muscle mass and hindering muscle recovery post-workout. Translation: less lean muscle mass and more time between workouts, which will curb your results. 

Stress

If you feel stressed balancing a career, family, and everything else life is throwing your way, you’re not alone. Stress levels can really go up in midlife, and if you don’t have good stress coping techniques, you will have excess cortisol,” says Dr. Tandon. “When you have high levels of the stress hormone cortisol, your body hangs on to fat.” Studies show that high cortisol levels are linked with more fat concentrated around the midsection. According to research, this type of belly fat is associated with a higher risk of heart disease. 

“As we get older, it’s not a coincidence that we have more belly fat and our risk for heart disease goes up,” says Dr. Tandon. “That’s one reason we need to be really cognizant about improving our body composition.” 

How to Revamp Your Routine 

While change is inevitable, you have the power to shift and reshape your wellness routine. The first step is paying attention. “I encourage people to become more in tune with their bodies,” says Dr. Tandon. “If you notice a loss of muscle tone, change in weight, or dip in energy, you can strategize.” Here are some places to start. 

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Check Your Levels

Hormone levels, thyroid, and vitamin deficiencies can majorly impact your body composition. Knowledge is power, so your first step is learning your levels. With the Lifeforce Diagnostic, we measure 40+ biomarkers that impact physical and mental performance, including testosterone, DHEA, thyroid hormone, growth hormone, and more. You won’t have to guess what’s getting in the way of your goals; you’ll know exactly what needs optimizing. You’ll then speak with a Lifeforce Medical doctor and get a personalized action plan for how to enhance your levels, plus performance guides to coach you on optimizing your diet and exercise. 

Boost Your Protein Intake

Like with vitamin D, our bodies don’t absorb protein as effectively as we age. Plus, we tend to eat less protein as we get older, says. Dr. Tandon. “People are often told to lower their fat intake, so they reduce meat, eggs, and other protein sources.” 

But you don’t want to skimp on this powerhouse nutrient. Amino acids are the building blocks of protein and they’re essential for repairing and rebuilding muscle, according to Dr. Tandon. When you work out, you experience tiny tears in your muscle fibers. Protein helps repair those tears so muscles can grow back stronger. Studies show that eating protein post-workout can help optimize muscle repair and growth. 

Research also links protein to lean body mass. Studies found that a high-protein diet is associated with greater weight loss, fat mass loss, and preservation of lean mass. Dr. Tandon suggests enjoying lean proteins like chicken, turkey, fish, nuts, eggs, and legumes. 

Drink Up 

Hydration is essential for every system in the body — and that goes for lean muscle and body composition, too. Research has shown that water intake is associated with lower body weight, body fat mass, and waist circumference. Another study found that proper hydration is linked to lean muscle mass, muscle strength, and muscle functionality in older adults. Plus, H20 carries nutrients and oxygen to your cells and helps maintain an electrolyte balance, which are both essential for supporting an active lifestyle. 
The U.S. National Academies of Sciences, Engineering, and Medicine recommends that men consume approximately 125 ounces of water per day and women take in about 91 ounces. Keep a water bottle with you at work and when you’re on the go so you always have it handy. You can also try tracking your water intake in a journal or an app to keep it top of mind.

Why Your Body Is Changing Even If Your Diet and Exercise Aren’t

Hit the Weights 

Strength training is the number one way to build muscle, says Dr. Tandon. “With cardio, you just don’t get that same improvement in lean muscle mass.” Research shows that building muscle increases your metabolic rate, allowing you to burn more calories at rest. Plus, studies show that your metabolic rate can be boosted for up to 72 hours after a strength training session. Another perk of lifting weights: “As you build more muscle, you can naturally improve your testosterone levels, which makes you leaner.” 

If hitting the weights sounds intimidating, don’t worry. “Strength training doesn’t have to be excessive,” notes Dr. Tandon. “Just 20 to 30 minutes a few days a week goes a long way.” She advises to focus on larger muscle groups like your glutes and quads because those will be the most efficient at impacting your metabolic rate. If you don’t belong to a gym or don’t have equipment, Dr. Tandon suggests starting with bodyweight exercises. She says, “Something as simple as push-ups, bodyweight squats, or abdominal work can be really effective.” 

No matter what exercise you choose, the key is to keep it moving. “When you’re not using your muscles regularly, it leads to atrophy,” Dr. Tandon says, referring to the wasting or thinning of muscle mass. It’s like the “use it or lose it” principle — you definitely want to use those muscles.

Uplevel with Nutraceuticals 

Sleep, stamina, and vitamin deficiencies can all impact your body composition. At Lifeforce, we have ways to enhance all those areas. If a poor night’s sleep is getting in the way of your goals, Dr. Tandon suggests trying Peak Rest, a premium, high-impact formula that regulates your sleep-wake cycle and calms your mind. Looking for an extra boost to fuel your workouts? Dr. Tandon recommends Peak Rise, which keeps you energized and focused without a mid-afternoon crash. It also extends the duration of caffeine by up to three times. 

If your diagnostic reveals that your vitamin D levels are low, Lifeforce D+K will be your new go-to. It’s the only formula of its kind to feature ampli-D®, which is clinically proven to raise vitamin D levels three times faster and more effectively than other types. Plus, the addition of vitamin K ensures that calcium is deposited in the bone instead of the arteries, which is vital for heart health. 

“People’s goals get sabotaged by their hormone and vitamin levels,” says Dr. Tandon. “Once we correct that, you can break that barrier and get into a positive cycle to see results.” 

Uncover your hormone and critical nutrient levels with the Lifeforce Diagnostic. Learn more here.

This article was medically reviewed by Vinita Tandon, MD, ABIM Board Certified in Endocrinology and Metabolism.