Females are not just smaller versions of men. The stark reality is, women are different, in more ways than your probably know.  When it comes to fat loss, they are a different kettle of fish…

It has long been known that women have a more difficult time losing body fat than males.

It’s hormones.

It’s PMS.

It’s menopause.

The truth is, it’s a combination of the above, and there are a myriad of reasons why females have a much harder time getting leaner than males, so let’s explore this…

So why do women have a harder time getting lean?

1. For The Human Race To Survive.

The reason why females struggle to get lean and lose body fat is an evolutionary consequence.

You see, the female body evolved to handle energy deprivation due to the fact that they are responsible for the survival of the human race.

Once a male has played his somewhat insignificant role of insemination, the rest really is up to the females.

The mother must fall pregnant.

Bare the child.

Give birth.

Feed their baby.

And nurture their child until they are old enough to hunt, gather, forage and find a companion for themselves to reproduce with.

As a result of this evolutionary role that women play, they need to survive long after they’ve done the deed… Us males, well once we’ve done our job, there isn’t much else we contribute to the evolutionary process.

But what does this have to do with fat loss?

Well, quite simply, body fat is conducive to survival.

More fat results in more energy which increases the duration that one can endure without food. It protects vital organs, insulates the body and improves hormonal function, all necessary for survival.

This is the ‘distal’ reasoning for why females don’t lose fat easily and fat loss, and too much of it, indicates energy deprivation which is counterintuitive to their evolutionary purpose.

You see, females and fat storage is kind of important, so as a consequence of this, women drew the short end of the stick when it comes to getting lean…

2. Body Size & Energy Expenditure

Another reason why females struggle to lose fat is that on average, women are 10% lighter than males.

It sounds insignificant, but the accumulative effect of being smaller can definitely make getting lean even harder.

Typically, the size difference is attributed to females having less Lean Body Mass.

A lot of the previously considered gender differences for fat loss are primarily due to the difference in body size between males and females.

By being smaller, females have a lower Resting Metabolic Rate (RMR), which means they are burning less calories at rest.

Females also burn fewer calories when eating via the Thermic Effect of Eating (TEF) because they eat less than males.

Also, women burn less calories during activity and throughout the day due to have less body mass (AT + NEAT).

It is due to the differences in body size, and a result of having less muscle mass, that females typically can’t perform the same as men. Now before I offend anyone out there, I am speaking in the general sense, because I am well aware of how some of my female athletes out perform the blokes…

But generally speaking, women lift lighter weights, don’t run as fast, are less explosive and so forth.

All of this combined means that women are burning less calories over 24 hours than males…

3. Female Hormones & Body Fat

Ok, this is where it gets interesting, in a weird way…

Men’s hormonal levels are quite stable across the month.

The main player in the male system is testosterone. Testosterone levels are relatively constant throughout the month, which means that a lot of the hormonal fluctuations females have to deal with, are absent in males.

Females, as we all know, are hormonally less ‘stable’ during the month.

Their hormones are changing week to week, and the changes in Estrogen and Progesterone cause a myriad of complications when it comes to appetite, metabolism, fat storage and fat mobilization.

Fat Storage 1o1…

In a nutshell, fat can come from three places:

  1. Intra Muscular Triglycerides – Fat that is located inside skeletal muscle fibers.
  2. Subcutaneous Fat – Subcutaneous fat is the fatty or adipose tissue lying directly under the skin layers. Subcutaneous translates to “under the skin.” It contains not only fatty tissues but also blood vessels, which supply the skin with oxygen, and nerves.
  3. Visceral Fat – Body fat that is stored within the abdominal cavity and is therefore stored around a number of important internal organs such as the liver, pancreas and intestines.

Men typically have more visceral fat as a consequence of having higher testosterone levels.

Women however, have a greater percentage of subcutaneous fat, especially in the lower body due as a result of their evolutionary purpose, along with their higher oestrogen levels and greater percentage of alpha receptors. Not to mention that during the day, females will be burning carbohydrates, not fat, whereas men will be the opposite.

Visceral fat can be lost with ease, which means that men will lose weight at a quicker rate initially.

Subcutaneous fat however, is oxidised at a much slower rate when compared to visceral fat and intramuscular triglycerides, and this is important for female fat loss, as the substrate (fuel) they use for exercise and when at rest is critical to the preservation of fat stores.

4. Substrate Utilization

Another difference between males and females when it comes to fat loss is substrate utilisation during exercise.

For example, during aerobic exercise, sure men and women burn similar amounts of fat, however it’s coming from different areas. As we know, women spare body fat, and thus will burn a higher percentage of intra muscular triglycerides than males.

Men will use more fatty acids, and have more upper body fat, which is easier to mobilise than fat stored in the lower body which has a higher percentage of alphas receptors.

Here is a quick overview:

Men During Exercise – Greater percentage of carbohydrates.

Men After Exercise – Greater percentage of fat.

Females During Exercise – Greater percentage of fat.

Females After Exercise – Greater percentage of carbohydrates.

What this means in the grand scheme of things, is that although females may be burning fat during their one hour workout, they will primarily be utilising carbohydrates and glycogen for the remainder of the day, and utilise intramuscular triglycerides during exercise.

Again, another strike for females and getting lean.

5. Metabolic Adaptation To Diet

When you eat at a prolonged calorie deficit, your body weight changes. So too does the amount of calories your body burns each day at rest, during daily activities and there is also a decrease in energy expenditure as a result  of being smaller – losing weight.

For example, if you start your fat loss phase weighing at 60kg and require 1600 calories to be at a small calorie deficit, a 5kg loss ( body weight of 55kg) may see that you require 1400 calories to achieve the same deficit.

However, fat loss for males and females alike, isn’t that simple, and the reason for this is called metabolic adaptation.

Simply put, metabolic adaptation is the slow down in metabolism that occurs during dieting which cannot be accounted for by change in body weight.

You may predict your energy demands based on changes in body weight, but there are adaptations to the hormonal and nervous system that result in a slower metabolism than predicted.

This can happen in all four components of energy expenditure – RMR – TEF, EAT, NEAT.

The adaptive component, the drop that’s larger than predicted (hormonal, nervous system, leptin, thyroid, muscular efficiency and so forth) means that you’ll need to eat even fewer calories to achieve the same amount of fat loss.

There are indications that female body regulates energy homeostasis differently to males, and their metabolisms adapt much quicker than males.


We know that leptin plays a key role in energy homeostasis, and is critical in fat loss. Leptin sends signals to the hypothalamus in response to food intake, and is also responsible for menstrual cycle function and dysfunction.

In response to diet, leptin drops quickly, a drop of around 50% in the first week.

Women’s leptin drops even faster than males, around ~20% faster. It has also been shown that the female brain responds quite differently to energy deficits than males. This causes a much faster adaptation to their metabolism, which is why large calorie deficits and crash dieting doesn’t work well for females, as it forces all of their systems to fight and adapt even harder to prevent fat loss and preserve energy and hormonal function.

This is why females diet for long durations or drastically restrict calories, amenorrhea, the oss of menstrual cycle, can occur.

6. The Menstrual Cycle

It should come as no surprise that the menstrual cycle can wreak havoc with a females attempt to lose fat and get lean. From fluctuations in mood, energy, cravings to water weight, everything but the kitchen sink is thrown at a female from month to month hormonally.

Now, before we continue, it is important to note that there is a large inter-individual variation when it comes to the effects of menstruating. Some women have no issues whatsoever, and some women can barely get out of bed, and I am speaking from both anecdote and what the literature has observed.

So let’s take a quick look at what happens over a 28 day monthly cycle…

Day 1-14 – Follicular Phase – Estrogen is dominant.

Day 14 – Ovulation – Relaxin Increases.

Day 15-28 – Luteal phase – Estrogen crashes, progesterone spikes.

Day 29 – Menses.

In the first 14 days of the follicular phase, the follicle, (which contains the female egg), is maturing getting ready for the release of an egg under the influence of FSH – follicle stimulating hormone. Estrogen is relatively constant, and then spikes just before it crashes at the end of this phase.

In the luteal phase, once ovulation has occurred, there is the transformation of the follicle into the corpus luteum once ‘explodes’, and the egg is released. This phase is triggered by a large surge in lutenizing hormone which causes the follicle to release its egg.

Progesterone is the problem hormone and directly stimulates fat storage, and it is during this phase that there are increases in energy expenditure, body temperature and increases in hunger – cravings carbs and fats during this time which can result in operating and fat gain.

This is when a female is most fertile, and thus it’s time for pregnancy and the body needs calories to ensure the body can be fertilized.

All of this effects water weight, appetite, fat mobilisation, fat storage, mood, performance and everything else in between.

Water spikes during the menstrual cycle…

There are two main times during the month when body weight increases due to the menstrual cycle.

  1. After first 14 days when Estrogen increases, water weight increases due to changes in sodium storage.
  2. And again in the second half of the luteal phase, when PMS occurs, there is another spike in water weight.

When it comes to water gain, progesterone actually blocks the receptor involved in water retention and thus when progesterone levels drop, there is an increase in water weight.

Although this is all great on a piece of paper and reading it on your tablet, the real world is much different, and woman show far too much variability that is too unpredictable to determine the exact timing of and body weight changes during their cycle.


Although it may seem that the fat loss chips are stacked against females, it doesn’t mean that it is impossible to get lean. I have time and time again been able to help my female physique athletes and clients alike get into great shape.

There are a number of practical things that must be taken into consideration to be successful in your fat loss attempts.

  1. Don’t weigh daily or even regularly during the week. Remember, your weigh in’s won’t be consistent and this is normal and healthy and won’t affect your overall fat loss. There is nothing that you can, or should be doing, to reduce the effects of the water gain caused by your cycle. Just understand that your weight will fluctuate during the month.
  2. Keep track of your monthly cycle and assess when and how much your body weight changes, your cravings, mood, energy and performance at various times of your cycle.
  3. The menstrual cycle also makes tracking diet results harder, as checking weight can be changing week to week and water weight can throw of measurements. Measure once a month at the same time of the month, compare weigh ins on the first week of the follicular phase each month. Alternatively, take an average over the 4 weeks of the month and compare trends to previous months to assess progress.
  4. Don’t crash diet, as large calorie deficits will not only result in the absence of menstrual cycle, but increase the speed of metabolic adaptation.
  5. Include dietary re-feeds. Having structured and regular periods (24-48 hours) of high calorie and carbohydrate intake to increase leptin which can reverse the metabolic adaptations to dieting somewhat, and increase the likelihood of a healthy menstrual cycle.

The Bottom Line…

Ladies, it is important to understand your cycle…

I mean, I’m not a female, and I know a hell of a lot more about my female athletes menstrual cycle than they do!

If you don’t understand your menstrual cycle, you may find yourself disappointed and potentially losing motivation when weekly weigh in’s are unpredictable and you’re not making progress in the gym.

*** It is important to note that the content in this article is based on a regular, healthy menstrual cycle. It doesn’t take into consideration the effects of birth control and other issues such as menopause, polycystic ovary syndrome, irregular menstrual cycle and complications with the female hormonal system.

Coach Jacob


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