The question of how to lose fat in the abdominal area is one that plagues the majority of people living in Westernized countries at some point in their lives, even if they exercise regularly and follow a relatively healthy diet. Getting rid of body fat in the abdominal region is key to the much sought after six pack and a ‘flat stomach’ which many erroneously associate with a truly fit physique. While a small waist and flat midsection is highly coveted in developed countries where the most of the population is overweight, relatively few individuals who are overweight are able to reduce the fat around their midsection. Thus it is logical to assume a disconnect between the popular practices for reducing fat around the abdominal area and what actually works. We have evidence that whole body fat oxidation increases with exercise intensity up to 55-65% of VO2max, but decreases at higher exercise intensities.[27,32,33,44] As a result, aerobic exercise (cardio) has been widely recommended as a tool for managing obesity, but there are some problems with applying this exercise for fat burning concept in the real world. One issue is that the recommendations are made based on experiments involving overnight fasting and most importantly, researchers did not record whether these increases made any difference in fat burning over a 24-hour period. Longer term studies using indirect calorimetry found no increase in 24-hour fat burning after exercise when energy intake is balanced,[1] with measurable fat oxidation increasing only when exercise is performed before breakfast.[11] Even then fat burning does not perfectly explain the fat reducing outcome of high intensity exercise which does not use fat as a fuel source[34] and any increased fat burning from exercising in a pre-breakfast fasted state pales in comparison to increased fat burning due to dietary interventions.[1,3,11] (See my article- 6 Pack Abs ̶ It’s Not What You Do It’s What You Eat). In this article we will take a look at the current research on reducing abdominal fat and put forward the notion that it is time to stop thinking in terms of trying to burn body fat through exercise, but instead focus on increasing lean muscle mass and employing muscle building high intensity training modalities in order to reduce body fat. Thanks as always for taking the time to read my work and do share it with anyone you think might find it to be of interest.
Understanding The Role Of Abdominal Fat
Sometimes it can feel like the fat around your midsection is an immovable mass that refuses to go away. The truth of the matter though is that the fat in your abdominal area is constantly being released into your blood stream as a source of fuel for your muscles. So much so that if you haven’t eaten in a while, fatty acid concentrations in the veins of the abdominal region can be as much as three times higher than those in your lower arms.[4] (Differences in concentration of fatty acids and glycerol between forearm and abdominal venous blood briefly goes down to similar levels an hour or so after eating.) This shows that abdominal fat cells are continuously discharging out fatty acids into circulation, which raises an interesting question. Why do so many people have trouble losing fat in their midsection if our bodies are constantly releasing fat acids from the abdominal area?
The Link Between Reducing Abdominal Fat & Building Muscle
The fat tissue in your abdominal area is constantly releasing fatty acids to be used by muscles as fuel
One of the answers seems to be linked to the amount of lean muscle mass on the body as there is compelling evidence that skeletal muscle dictates fat cell mass. Firstly, tissue growth has a powerful effect on increasing whole body hydrocarbon demand and we can see this in cancer patients with tumors who report significant weight loss without any changes in activity or dietary intake.[5] In fact, sudden unexplained weight loss can be a sign of a possible tumor, which is why doctors universally ask if you experienced any out of the ordinary weight loss during medical check-ups. Muscle growth elicits the same effect and reduces fat stores. In experiments with animals that were genetically altered with myostatin inhibitors and other genetic manipulations to increase their muscle mass, researchers noted a consistent decrease in body fat levels as a result of the muscle mass increase.[6,7] Human tests show the same outcome as elderly men with reduced gonad functions treated with testosterone injections show a decrease in fat mass over time as their lean body mass increases.[28] Now it should be noted that while muscle growth does increase basal metabolism, it is important to remember that in the aforementioned studies, energy intake remained the same before and after the increase in muscle mass. Pseudo-scientific fitness gurus would have you believe that a pound of muscle mass can increase metabolism by as much as 50 calories a day, which is not only mathematically impossible but not based on any solid scientific evidence.
The exact increase in calories burned per pound of muscle at rest is not exactly known, but it is probably no more than 6 to 10 extra calories per day. A number easily offset by poor diet choices as it is a little known fact that obesity also increases muscle mass[37] and the increased energy expenditure associated with greater muscle mass in obese individuals is completely offset by excessive energy intake. Giving further credence to the fact that diet remains the most important factor in fat loss, as increasing muscle mass alone cannot compensate for a poor diet.[38] That said, the increased muscle mass in overweight individuals can be positively utilized to facilitate fat loss in the abdominal area and overall through the implementation of high intensity training modalities that increase the hydrocarbon fuel demand of the muscles worked.
The Role Of High Intensity Training In Reducing Abdominal Fat
The more muscle mass you have the greater the demand for more fat and other hydrocarbon sources for fuel replenishment and repair after intense workouts which can reduce abdominal fat if energy intake is not excessive.
Energy to provide ATP for muscle protein turnover is largely derived from the oxidation of fat, which is the preferred energy fuel source of resting muscle mass,[39] and as we mentioned earlier, abdominal fat tissue is continuously releasing fatty acids before meals, with lean muscle tissue being a major consumer of fatty hydrocarbon sources.[3,4] Now after meals insulin levels increase and one of the properties of insulin is to stimulate the release of hydrocarbon sources from the intestines in order to replenish fat stores in adipose tissue. Introduce exercise that either brings about a state of overload or is of a high intensity and in keeping with the 2nd law of thermodynamics the stress will bring about a state of disorder in muscle cells. In order for those cells to return to a stable condition, damaged and energy depleted muscle fibers will demand more fat and other hydrocarbon sources for fuel replenishment and repair. Thus creating a state of negative energy balance in abdominal fat tissue stores which will not be fully renewed as an increased amount of hydrocarbon fuel sources will instead by diverted to muscle cells, provided of course that energy intake remains constant.[35] That being said, individuals with more muscle mass, who train at sufficiently high intensity would naturally have lower body fat levels than those with lower levels of skeletal muscle tissue provided that energy intake remained in balance or slightly below resting energy expenditure levels with a high protein diet and moderated carbohydrate intake.[40] This is one of the reasons why high intensity forms of training, while not inherently fat burning, still have a greater effect on reducing abdominal fat than low to moderate intensity exercise, [34,35] and why a program of resistance training is vital to reducing abdominal fat.(See my article How Muscles Get Bigger & Stronger)
Diet is the main component of losing abdominal fat as excessive energy intake and or carbohydrate overfeeding can suppress fat burning and offset any benefits of muscle building exercise.
The Importance of Diet In Reducing Abdominal Fat
First and foremost, diet is and always will be the most important factor when it comes to fat burning. If calories consumed equal calories expended, carbohydrate oxidation increases and fat oxidation decreases.[31] On the other hand, if you consume less calories than is expended on a daily basis, carbohydrate oxidation decreases and fat oxidation increases. What you eat also affects fat burning, as an excessive intake of carbohydrates creates a profound shift in fuel utilization, suppressing the oxidation of fat and increasing carbohydrate oxidation. Interestingly enough consuming fat does not make your body burn more fat, nor does it increase energy expenditure the way protein does.[30] So the typical high fat and high carbohydrate diet common in the developed world is a critical step if you want to make changes to your midsection.
Exercise Is Not The Best Prescription For Fat Loss
It might sound counterintuitive but our bodies burn more fat when we are inactive and relies less on fat as an energy source as you become more fit!
Now that we understand the importance of diet, it is clear to see that trying to use exercise by itself as a fat burning tool will always fail as it cannot compensate for poor eating choices, nor can you burn off more fat by simply doing more exercise as our bodies simply do not work that way. Compounding the problem of relying on exercise to burn fat is that from what we know about how our body reacts to exercise on a cellular level exercise can also decrease fat utilization. Lipoprotein lipase is an enzyme in blood capillaries that plays a critical role in breaking down fats in the form of triglycerides into fatty acids. This is an essential step in the partitioning of fatty acids into either fat or muscle tissue. In a well-trained individual, the ratio of lipoprotein lipase activity in fat tissue versus muscle tissue is approximately eight times more than it would be if their lifestyle changes from being active to inactive.[26] What this means is the more sedentary you become, the more your body delivers fatty acids to existing fat tissue to be stored as opposed to sending it to your muscles to be used as a fuel source. This is one of the reasons why inactivity can lead to obesity.[26] Now while many believe that endurance type exercise makes our bodies burn more fat, it’s not quite that simple. Endurance training increases mitochondrial density in muscle cells, which increases the ability of skeletal muscle to oxidize fat,[28,29,30,31] but at the same time the more you regularly exercise the more your body relies on carbohydrate in the form of glycogen stored in skeletal muscle as a fuel source.[27] With a proportional DECREASE in dependence on energy from circulating fatty acids which come from stored fat tissue. [27] It might sound counterintuitive but our bodies burn more fat when we are INACTIVE, and relies less on fat as an energy source as you become more active.[3
No comments:
Post a Comment