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Tuesday, July 23, 2024


When we think about fat loss, one often overlooked aspect is how fat loss differs between men and women. How many times have you heard that a husband and wife go on the same diet and the man seems to lose weight faster and with seemingly less effort?

There are reasons for this phenomenon, and understanding the physiology and mechanisms can hopefully shed some light and provide some answers for why women are different from men when it comes to fat loss.

Mark Kini To set the stage, let’s talk about where body fat comes from. When we eat food, we break it down and use the calories for basic functions and energy needs of the body. Someone’s basal metabolic rate (BMR) refers to how many calories that person needs/burns at rest. These calories go toward functions like breathing, cellular growth and repair, regulating body temperature, circulation, hormone production, etc. Someone’s total daily energy expenditure refers to how many calories that person needs/burns, including those additional calories their body burns for daily activities like work-related movement or exercise.

So where does body fat come in? Calories that go beyond the needs of the body’s basic functions or daily movement get stored in a variety of ways, and one of them is body fat. Think of this body fat as backup energy. 

Tune into Eliza Nelson’s weekly podcast “Breakthru” on Spotify where she discusses fitness, identity, and mental health and how to commit yourself and prioritize goals through difficult times.
Women in general have a lower metabolic rate than men because they tend to be smaller and have less muscle mass (which is a metabolically expensive tissue to make and preserve). Historically women are also more prone to diet and calorie restriction, which lowers their metabolic rates even further over time. Moreover, there is a haste that is pushed on women to lose weight as quickly as possible (e.g., crash diets, six-week detoxes, etc.) and because that requires a large calorie deficit, calories are cut well below their BMR (basic caloric need of the body). This causes obvious issues. Women’s physiologies are greatly susceptible to outside factors because their hormone balance is much more sensitive than a man’s mainly due to having to maintain an inner homeostasis to allow and sustain a potential pregnancy. So, not only is too much of a caloric restriction a problem for a woman’s inner functioning, but performance in the gym is affected, sleep quality or amount can suffer, and movement throughout the day tends to decrease—just because they don’t have enough energy to do anything extra. Unsustainable dieting practices can cause an early ditching of the uncomfortable routine, and a rebound regaining of body fat typically occurs.

On top of the typical dieting cycle, which lowers metabolic rate (i.e., calories burned at rest), women’s bodies are better at storing and conserving energy—in this case in the form of body fat—due to their energetic needs especially when it comes to reproductive roles. A woman needs a lot of energy to produce a singular egg and if pregnancy occurs, they need to be able to draw from energy to support the development of the baby. Furthermore, once the baby is born, the body needs sufficient energy to produce breast milk even if food supply is low. This is part of why women’s bodies need to be able to conserve energy and have it in reserve, partially in the form of body fat.

Another factor to consider regarding how women’s metabolisms are different than men is that although women tend to burn a higher percentage of fat during an hour of exercise (as opposed to carbohydrates) than men do, women tend to burn a higher percentage of carbohydrates throughout the day instead of body fat. Women also tend to have less muscle mass than men and muscle helps to metabolize and store carbohydrates via insulin receptors. Better/efficient storage for carbs means less carbs (sugar) circulating in the bloodstream means that more fat can be released into the bloodstream in the form of free fatty acids and burned. If blood sugar is high due to poor diet or stress, burning body fat is very difficult.

What are some tips for women to burn body fat?
  • Try less aggressive calorie deficits and more sustainability so metabolism, hormone balance, and performance are not affected as much
  • Focus on quality of micronutrients in diet and aim for around 30-40g of protein in each meal to manage blood sugar, satiety, and body composition
  • Adopt strength training to increase metabolism, blood sugar, and fat burning at rest
  • Manage stress to help body relax and not hold onto body fat due to cortisol, hormone imbalances, sleep disturbances, and downregulated metabolism
  • Accept that women’s bodies are naturally going to carry more body fat than men (have roughly 10-12 percent more body fat than men and also have more total number of fat cells as well)
  • Reduce or eliminate alcohol consumption which are extra calories that offer no nutritional value, increase internal stress, halt body being able to burn fat while breaking it down. Alcohol also and stresses the liver, an organ that detoxifies blood, breaks down fats, and produces energy

Mark Kini is the President & CEO of Boston Chauffeur. He can be reached at mark@bostonchauffeur.com. Eliza Nelson is a personal trainer and owner of Breakthru Fitness. She can be reached at elizanelsonfit@gmail.com