How to improve your body composition without miracle diets

Balancing the quantity and percentage of water, fat and muscle mass is essential to staying healthy

A young woman does crunches in a gym with a trainer.Srdjan Pavlovic (Getty Images)
Sara Tabares

As summer arrives, there is a rise in advertisements for methods promising effortless weight loss. Billboards, shops and posters tout what we “could achieve” if we just paid for their services — feats such as “a six-pack” or a “summer body.” Social networks become a runway of before-and-after photos. Such marketing schemes play on our emotions, making a business out of creating false expectations and encouraging us to compare ourselves to others. But your body is your ally, not your enemy. Understanding how it works will stop you from wasting time and money on scams.

We are all made up of fat, muscles, bones and water. Not everyone has the same body composition, and it can be changed, but not by doing just anything. What’s more, we all have physiological differences and come from different contexts, and our bodies do not all react to exercise in the same way. Someone can be the same height and weight as you, but have more fat and less muscle, implying different health concerns.

The quantity and percentage of each of these components — water, fat, muscle and bone — varies depending on factors such as age and sex, among others. Men tend to have a lower fat percentage. Fat content tends to increase with age, particularly in women after menopause, when the production of estrogen stops.

‘Problem areas’

“Look, I’ve tried and bought everything. I’ve destroyed myself exercising, and my belly doesn’t go away,” said one of my clients, Carmen, who recognizes that, at 48 years old, she had become “addicted to trying all kinds of targeted workouts to eliminate belly fat.” The waist, legs, gluteus and triceps are all areas that store fat. There are many methods without scientific basis that promise to make those points disappear through targeted exercise. “Explain to me how the body burns fat and why this” — she pointed at her stomach — “is still here. It’s also in my hips. Give me any workout,” she said.

Fat, as scientific studies explain, is primarily stored in adipocytes, fat deposits through the body. The adipocyte is the cell found in the adipose tissue, but it is not the only cell, or the most abundant one, in adipose tissue. There are also stem cells, pre-adipocytes, macrophages, neutrophils, lymphocytes and endothelial cells. The increase in size or numbers of adipocytes and the type of lymphocytes and macrophages is linked to metabolic syndrome illnesses, a group of risk factors including excess abdominal fat, cholesterol, insulin resistance and hypertension, among others.

Fat location can be a predictor for illnesses. We have two types of fat: visceral and subcutaneous. An increase in visceral fat — which covers our organs — is associated with a greater risk of the aforementioned illnesses. Subcutaneous fat is the fat that we can pinch. It can be converted into free fatty acids to move into the blood and go to where it is needed. Regardless of where they come from, all free fatty acids are one heartbeat away from where they need to go. Imagine that you are going to build a structure that requires bricks, and all of them need to pass through a warehouse before being put into place. It doesn’t matter if they are created near or far from where they will be used. The same is true for subcutaneous fat. Through lipolysis, triglycerides present in subcutaneous fat liberate fatty acids that pass into the bloodstream, to the heart and then to wherever they are required.

Myth: Sit-ups will eliminate fat

“So doing 100 sit-ups won’t help me eliminate fat?” Carmen asked. During exercise, free fatty acids are used as fuel. They can come from any part of the body, not from the specific area being worked out. “Working out your midsection can make you stronger, but it won’t reduce your localized fat,” I responded.

Studies have shown that exercises for specific body parts do not affect the subcutaneous fat of that area. That said, we need fat to live. It is essential for the functioning of our bodies, and it stores the energy that is needed for most of our activities. There is a healthy margin, and the risk of certain illnesses and premature death increases when we are both above or below it. In women, a lower fat percentage can provoke hormonal changes that can cause amenorrhea, the loss of menstruation. In men, it can also lead to hormonal problems that affect the body’s functioning.

Strength training

“My metabolism has slowed down,” Laura told me with a concerned expression when we first met. “I don’t know what happened, but everything I eat stays inside, and that didn’t happen before.” The metabolism is the amount of energy that the body uses. Everything the body does requires energy. The amount varies from person to person. Laura and another woman may have the same workout, eat the same diet and weigh the same, but even so, they will lose fat in different ways. We all have different metabolisms.

In the book Secrets to Successful Program Design, authors Crosgrove and Rasmussen explain that most of the total metabolism comes from the resting metabolic rate, the number of calories needed to maintain the body’s basic functions without any activity. Strength training increases our lean muscle. The more we have, the more quickly our resting metabolism functions. Muscles are our natural fat burners. That means that weight training increases our metabolism, causing our bodies to consume more calories, which could lead to a reduction in fat.

From theory to practice

The number on the scale will not tell you how much of your body is composed of fat and muscle mass. A dual-energy X-ray absorptiometry (DEXA) scan or a bioelectric impedance analysis can. The data should be interpreted by a specialist, such as a dietician-nutritionist, endocrinologist or sports medicine doctor. Exercising correctly requires individualization, planning and order. If your objective is to improve your body composition, consult with a sports scientist who can prescribe a workout specific to your circumstances.

Combine aerobic exercise with strength training. The effects on body composition have been studied in the meta-analysis published by the journal Frontiers in Immunology. Researchers found that combining aerobic exercise and strength training is best for improving body composition and inflammation in people who are overweight and/or obese. Interventions that combine high-intensity aerobic training and high-load strength training are the most effective ways to decrease abdominal adiposity, improve lean mass and increase cardiorespiratory fitness. Aerobic exercise leads to changes in aerobic capacity and lipid profiles, and increases insulin sensitivity. In addition, particularly in adults suffering from obesity, it can lead to a decrease in the production of leptin (a hormone involved in body weight regulation), which in turn contributes to a reduction in adipose tissue accumulation. It also increases levels of growth hormone and adiponectin, which play a role in reducing abdominal fat and the circulation of free fatty acids. Strength training has the potential to change the metabolic properties of skeletal muscle. It causes an increase in lean body mass which, in turn, influences an increase in resting metabolic rate.

If you strength-train, prioritize exercises that move large muscle groups (squats, lunges, presses and pulls).

HIIT (high-intensity interval training) involves short periods of intense activity (pedaling, for example), immediately followed by recovery periods. A review published by Obesity Reviews compared the effects of high-intensity interval training (HIIT) and moderate-intensity continuous training (MICT) for improving body composition in overweight and obese adults. The conclusion was that HIIT and MICT show similar efficacy on all measures of body composition. The studies suggest that HIIT may be more efficient — as it takes less time to perform and may lead to more adherence — for those who wish to begin a program aimed at fat loss.

According to World Health Organization (WHO) recommendations, adults should engage in moderate aerobic physical activity for at least 150 to 300 minutes a week or intense aerobic physical activity for at least 75 to 150 minutes a week. The WHO also recommends doing moderate or intense muscle-strengthening activities that exercise all major muscle groups two or more days a week.

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