Fat Loss: Men and Women Are Not Made Alike!

Men & women are not made the same - Some studies are suggesting that men and women may process, store, and use fat differently, both while exercising and while at rest. Learn more as I clear up the confusion about fat loss between the sexes.

If you ask the vast majority of women who has a harder time losing body fat, most of them will echo a resounding answer: we do! Most women feel that men have an easier time getting lean while they have this stubborn fat that just seems to stick around regardless of what they do.

It latches on to them and despite even the most good-natured diet efforts (and oftentimes, not so healthy diet efforts), they cannot get rid of it. Frustration sets in and they blame their gender for their troubles.

Is This Justified?

It's no secret that more and more people are becoming over weight. Just take a good look around you and it's clearly evident that there are more people who struggle with their weight than don't. It's a big reason why the fat loss industry is running like rapid fire right now. Almost everyone has some body fat they would like to lose.

With this prevalence on the rise, more and more research is being done as to what we can do to stop it and treat those who are already tipping the scales. Fat metabolism is the focus of this research and some studies are suggesting that men and women may process, store, and use fat differently, both while exercising and while at rest.

Fat Storage

Fat storage takes place when there is a surplus of energy supplied to the body; more than what's required to meet present needs. These excess calories will be stored in the form of a triglyceride molecule, which consists of three fatty acids held together by a glycerol molecule acting as a backbone. These triglycerides will usually be stored in the body fat cells, called adipocytes, however, a small amount can also be stored within the actual skeletal muscle, forming intramuscular triglycerides.

The muscular storage form, however, is vastly smaller than what's stored in the rest of the body, typically about 2000 calories worth of fat in the muscles in comparison to 50,000 or more calories stored in the body fat cells.

When fat is needed for energy by the body, the stored triglycerides in the body fat cells will be broken down during a process called lipolysis and then used to fuel the muscles in need.

It is important to note that men and women typically carry fat differently on their bodies; females carrying a greater portion of it in the hip and thigh area, while males tend to focus their fat in the abdominal region. Additionally, females do have a higher essential body fat requirement due to the fact that their bodies must be capable of giving birth and their reproduction system will require more body fat stores.

A healthy body fat level for women is the 20-25% range, while males can bring their body fat down to 10-15% and still be considered healthy.

Getting That Fat Moving

In order to effectively decrease body fat stores, you are going to have to mobilize the fat, which is the process of releasing the fat from the storage site into the body so then it can be broken down through the process of lipolysis.

Hormone sensitive lipase is the enzyme that works together with the hormone epinephrine, which stimulates the release of hormone sensitive lipase, to mobilize these fat cells and get them into the blood stream.

Once it's been stimulated, then hormone sensitive lipase will further work towards breaking apart the triglyceride into its fatty acid and glycerol components.

When you are performing cardiovascular work, the body will be more receptive to epinephrine, therefore there is an increased rate of lipolysis that will be seen.

Furthermore, individuals who have undergone a great deal of endurance training will also have an enhanced receptiveness to epinephrine. In their case, it will require lower levels of epinephrine to be released in order to trigger the fat cell release; therefore, they will start burning body fat more easily.

Those who are sedentary and overweight will have the opposite effect occurring, thus actually making it harder for them to lose body fat stores.

The two main receptors that epinephrine will target are alpha and beta receptors. When more receptors are available and when their sensitivity is increased, the body will be in a better position for lipolysis to take place.

The key factor at play here when discussing men and women and fat loss is that it appears as though body fat cells in the abdominal area are more sensitive to beta receptors than thigh fat cells are.

Because women typically tend to store more of their body fat in their thighs, while men store more in their abdominal area, as stated above, this could be one reason why women seem to have that "stubborn fat" that just won't seem to leave.

Estrogen's Role

Next, is a very different make-up between men and women when it comes to the sex hormones; however, this difference appears to tilt in the favor of women!

Estrogen seems to help increase the rate of fat metabolism while you are both exercising and at rest. One reason this occurs is because the hormone estrogen helps to stop the production of the hormone lipoprotein lipase, which is an enzyme that triggers fat to be stored in the body tissues.

Additionally, estrogen can help to increase the production of epinephrine in the body, which, as stated above, is a key regulator in getting the fat cells mobilized.

Finally, estrogen also increase the blood flow to the muscle cells during exercise through enhanced vasodilation, and with this increased blood flow comes a greater chance that the epinephrine in the body will react with the beta receptors to help trigger lipolysis.

RER and Females

Another potential difference in fat burning in females compared with males can be seen when you look at the respiratory exchange ratio (RER). This ratio tells us what percentage of the current fuel being used for energy is coming from fat and which percentage is coming from carbohydrates stores. Those who have a lower RER are using predominately more fat, whereas those who have a higher RER are going to be using more carbohydrates.

Respiratory Exchange Ratio
In one breath, you normally breathe in more molecules of oxygen than you breathe out molecules of carbon dioxide. The ratio between these CO2 / %O2 is the respiratory exchange ratio (RER).

Measuring this ratio can be used for estimating the respiratory quotient, an indicator of which fuel is being metabolized to supply the body with energy.

In studies done to compare men and women, working at the same percentage of intensity, it appears as though women maintain a lower RER than men, therefore, deriving more of the energy required to fuel exercise from fat.

One huge advantage to this is that with the reliance on fuel for fat, this means women will have an enhanced capability to spare muscle glycogen for fuel and this should help them to exercise for a longer period of time without experiencing as much muscular fatigue.


So, taking all these factors into account, it does appear as though there are some key differences between men and women when it comes to body fat storage, body fat release, and body fat use. However, you still must keep in mind that regardless of anything, you must burn more calories per day than you consume in order to lose body fat.

Even if women do have an enhanced capacity to rely on fat for fuel during exercise for example, if they are consuming a whole bunch of carbohydrates through the diet, these carbohydrates will just turn to more body fat anyway, replacing that which was burnt off.

It is also important for the women out there to remember that they will naturally always have a higher body fat level than their male counterparts will so to try and compete with males in this aspect is going to work directly against mother nature.

If they do succeed in bringing body fat levels incredibly low, a great deal of problems can set in with the reproduction system so often, it is just going to do you harm. While you might walk around proud to be sporting an ultra lean body, if you are placing your reproductive system at risk, you really must ask yourself if it's worth it.

Having a realistic goal in mind is a good place to start before you begin your diet, so you do not become discouraged when are you aren't dipping down to the single digits.


  1. Rasmussen, B.B., & Wolfe, R.R. 1999. Regulation of fatty acid oxidation in skeletal muscle. Annual Reviews in Nutrition, 19, 463-484.
  2. Vella, C. & Kravitz, L. (2002). Gender differences in fat metabolism. IDEA Health and Fitness Source, 20(10), 36-46.