Written by Dan Gwartney, MD
30 November 2018


Top 10 Proven Ways to Cut Body Fat



Every year, for every bodybuilder, it's a quest to shed fat to achieve a state referred to as "shredded," "peeled," or "cut." Off-season photos of the professional bodybuilders show that many binge and dine their way to obesity, yet within a matter of months, even weeks, they are once again posing in peak condition. Certainly diet, training and experience play a part in their ability to recover from dietary excess, but as many other athletes discover, discipline and willpower are not sufficient to account for the dramatic changes seen in the pros.

The following discussion addresses 10 of the more common and most effective means of achieving ultra-low body fat content used by the pros and high-caliber amateurs.While these methods are effective, many are illegal and most carry some element of risk. A fair question would be: Why they are used at all? The answer is simple; it's the same drive that causes shareholders to participate in insider trading, college students and professors to plagiarize and cheat, and politicians to lie. It's a desire to be the best, regardless of cost, risk or ethics. Thus, while the techniques may be unique to bodybuilding, or even sports in general, the phenomenon is not. Do not view the following information as an endorsement of these techniques. Rather, use it to approach the decision to use any of the methods described with greater foresight.

Stimulants are most easily understood as drugs or supplements that increase fat loss by providing a signal to the body that it's in an excited state and needs to be ready for action. Stimulants act either by stimulating the release of the "fight or flight neurotransmitter," norepinephrine (NE), prolonging its signal, or directly substituting for NE. There are two classic examples of stimulants used in fat loss by bodybuilders.

1.    Clenbuterol.  This drug is a direct beta-agonist, meaning it reacts with the exact same receptors NE uses to stimulate fat loss.1,2 Its main benefit over NE is that it's more specific, attaching only to the beta-2 type receptors. This is important because there are two classes of NE receptors in the fat cell membrane- alpha and beta. The alpha-2 receptors cause the opposite response of the beta receptors in regard to fat loss from the fat cell; alpha-2 stimulation blocks fat release3 while beta stimulation promotes fat release.4 So, clenbuterol is actually a more powerful fat release signal than epinephrine, which stimulates both alpha and beta receptors.

Clenbuterol, which is used outside the U.S. to treat asthma, has been discovered to also be anabolic when used in extremely high doses in animals.5,6 However, the levels needed to achieve this effect would be toxic, likely deadly to humans, so there's no practical anabolic effect from this drug.2 Clenbuterol is typically dosed in the range of 10-40 micrograms (not milligrams) per day, though some users will develop a tolerance to much higher doses.1 The effects of clenbuterol are short-lived, as the beta receptors will down-regulate, or burn out, within a matter of a few weeks, so many users will either use clenbuterol for only a short period or alternately go on and off the drug every couple of days. Clenbuterol has been associated with serious side effects in bodybuilders.7-9

2. Ephedrine/Caffeine Stacks. These supplements have typically been the top sellers for most health food stores, simply because they are effective. Numerous studies have been published demonstrating the combination of ephedrine and caffeine to be effective in accelerating weight loss, often preserving lean mass as opposed to the muscle wasting seen in unassisted fat loss.10,11 An unprecedented amount of controversy has arisen regarding the safety of ephedrine/caffeine supplements due to a number of adverse events reported among users. Ephedrine/caffeine use has been associated with a number of hospitalizations and several deaths.12-14 However, in studies where dosage was controlled and the subjects were monitored, ephedrine/caffeine has been declared to be safe and free from serious adverse events.10,11,15

The adverse reports led the FDA to ban the sale of synthetic ephedrine/caffeine (over-the-counter drugs under the jurisdiction of the FDA), which is unfortunate, as most studies used the more tightly controlled and regulated OTC drugs. However, recent published studies have shown that some of the herbal supplements are as effective and seemingly as safe as the OTC version.16,17 Bodybuilders use ephedrine/caffeine supplements not only for fat loss, but also because it is a stimulant and can aid in maintaining energy and motivation during training.

Unlike clenbuterol, ephedrine does not directly act on the beta receptors, but causes the release of NE, which stimulates both alpha and beta receptors, so the short-term effect of ephedrine/caffeine is not as dramatic as clenbuterol, but the duration of effect is much longer, with ephedrine/caffeine promoting weight loss for at least 24 weeks.10 Doses are typically in the range of 20-25 milligrams of ephedrine and 200 milligrams of caffeine one to three times a day.11,15  

cutfat-1Hormones of the body are involved in energy balance; altering the levels of these hormones can directly affect metabolism, increasing fat loss. Additionally, other effects of these hormones can alter either the rate of fat gain or where it's deposited. Use of hormones for fat loss is particularly dangerous, as an excess of any hormone can cause serious, even fatal consequences.

3. Testosterone and Other Steroids. These hormones are best known for the anabolic effect of the androgens upon the skeletal muscle, causing muscular growth and strength gains.18 By increasing the relative amount of muscle, steroids decrease the percentage of body fat. However, a number of studies have determined that either testosterone, esters or some of the other anabolic steroids can also directly impact fat loss.19,20 The oral drug oxandrolone seems to have a more pronounced effect on subcutaneous fat loss, though the exact cause for this has not been determined.21

4. Growth Hormone. This hormone affects nearly every cell in the body and excess use can cause permanent and disfiguring changes in appearance and health.22 However, GH has gained a great deal of notoriety as a repartitioning agent, meaning it moves nutrients from fat storage to the functioning muscles and organs.20 GH influences growth through a second hormone called IGF-1, but its effects as a fat loss agent seem to be more direct. GH excess interferes with insulin signaling,23 the main driver for fat storage, and also seems to accelerate fat release from fat cells.24-26 GH has been investigated for use in the morbidly obese28,29 and bodybuilders believe doses of four to six IU/day provide the benefits of GH use.22 GH should never be used, or even considered, without considering the serious and long-term consequences, physical and legal.

5. Aromatase Inhibitors. Aromatase inhibitors are drugs prescribed to women with advanced breast cancer to prevent the conversion of androgens to estrogens.30 Bodybuilders have recently added aromatase inhibitors to their arsenal to decrease the estrogenic side effects of many of the androgenic steroids.31 Testosterone and other steroids can be converted by aromatase into an estrogen,32 and an excess of estrogen will lead to water retention, breast development and fat accumulation. The fat cells have sex hormone receptors,33 and the presence of estrogen appears to increase both the number of fat cells and the amount of fat accumulated.34,35 Aromatase inhibitors can decrease the amount of estrogen in a man to very low levels,36,37 allowing bodybuilders to use the more androgenic testosterone esters without suffering from the estrogenic side effects, providing a leaner, harder appearance. Though a few centers have studied the short-term effects of aromatase inhibition in normal men,36,37 there's no long-term data on the effect of these medications. Currently, the selective aromatase inhibitors are limited in availability and are quite expensive.

6. Thyroid Hormone. The thyroid gland is the main regulator of the body's metabolic rate, adjusting the release of T4, a hormone with limited activity. T4 is converted into T3 within the liver and other tissues, with most of the cellular effects of thyroid hormone due to this form of the hormone. T3 is extremely potent and acts upon fat loss primarily by making the body more sensitive to the signal of NE, the stimulant neurotransmitter.38,39 Unfortunately, thyroid hormone, much like GH, is non-specific, meaning it affects nearly every tissue.
An excess of thyroid hormone leads to a potently catabolic state, and though weight loss will be significant, a significant portion of the weight loss will come from muscle wasting.40 Additionally, T3 excess can make the individual very sensitive to other stimulants, or even the natural release of NE, leading to dangerous heart rhythms, sleeplessness and irritability.41 Users need to be very conservative when combining T3 with any of the stimulants. While most thyroid hormone available comes from diverted (black market) T4, which is less effective and slow acting, the preferred drug for fat loss among users is T3, triiodothyronine. Users must increase the dose of T3 slowly and then taper off gradually to avoid overdosing or withdrawal. T3, used without anabolic steroids, will likely result in muscle wasting. Doses commonly used range from 25-100 micrograms daily.41

7. Cardio. After all the illicit drugs, it would seem a step backwards to consider cardio, but in fact, few of the drugs mentioned will provide much benefit without being used in the proper environment. Cardio is the bane of most bodybuilders, as they commonly do not care for the activities, nor expend the time needed for benefit. There are multiple opinions regarding when and how to do cardio: Low-intensity versus high, one session versus multiple, daily versus rarely, etc. There really is little practical difference between the various programs, none if the cardio is not done at all.

The effect of cardio, for fat loss, is to increase the activity-related calorie burning experienced by the bodybuilder.42 Resting metabolic rate is thought to rise with high-intensity exercise, though this remains to be proven for long-term conditioning.43,44 Considering that a greater muscle mass elevates the resting metabolic rate, as do stimulants (ephedrine/caffeine, green tea) that argument is marginal. Bodybuilders need to find an activity that will be maintained regularly, preferably every other day. The percentage of fat burned is higher for low-intensity exercise and best in the morning, before eating, with plenty of water and the use of caffeine.45 However, if that is not a possibility, other forms   still provide a benefit. Cardio can add to the caloric deficit, but it must be approached with care to avoid injury or muscle catabolism.

8. Ketogenic Diets. This type of diet has been popularized by Dr. Atkins, but represents the carb depletion phase used by bodybuilders for decades. Ketogenic diets require a great deal of willpower, as it severely restricts the amount of carbohydrates, foods commonly preferred in the American diet. Carb restriction will initially lead to irritability, loss of concentration and strength as a person adapts to it, but eventually behavior and training return to normal.

The purpose and intent of a ketogenic diet is to decrease the amount of insulin released into the body.46 Insulin is a major anabolic hormone, but unfortunately, it is the primary driver of calories into the fat cell and prevents the breakdown and release of stored fat, leading to a build up of body fat.47,48 When carbs are restricted, there is a large initial loss of weight, representing the water associated with glycogen stores in the liver and muscles. This can be as much as ten pounds in the first week. However, the fat loss from ketogenic dieting occurs more slowly and over a longer period.

Without insulin to block fat release, fat cells are much more sensitive and will respond more aggressively to stimulants and other hormones. By properly monitoring the calories and amount of dietary fat, ketogenic diets can lead to dramatic losses of body fat. Muscle can be negatively affected by ketogenic dieting, as insulin also drives nutrients (sugar, amino acids, creatine) into the muscle cell and prevents the breakdown of muscle protein. But, it appears ketogenic dieting preserves and may increase lean mass.46 Ketogenic diets can be followed for long periods, with many of the Atkins advocates adopting ketogenic diets as a permanent lifestyle.

Other Methods
9. Dinitrophenol. This chemical is used industrially for dye manufacture and in the production of explosives.49 Its effect on weight loss was discovered as a matter of occupational safety, with a number of workers in munitions plants suffering from unusual symptoms, even dying. It was found that they were inhaling DNP dust. DNP is a metabolic toxin, meaning it is a poison that affects the mitochondria, preventing them from being able to function.50 The mitochondria are the "powerhouses" of the cells, creating the energy molecule ATP from glucose or fatty acids.

In the presence of DNP, the mitochondria fail to produce ATP and energy production decreases as much as 60 percent, though the energy demands of the body remain stable, requiring more "fuel" to be burned to provide for the body's needs.50 While DNP is extremely potent, perhaps the strongest fat loss agent known, it is no longer used for weight loss.51 It was learned that DNP places the body under extreme oxidative stress, causing cataracts and other problems.49 Bodybuilders find DNP difficult to tolerate and typically use it only for short periods.

10. Other Items of Interest. A number of other products have promise for fat loss and are commonly used by bodybuilders. Yohimbine is a drug able to block the alpha-2 receptors, the receptors that block NE's fat-releasing effect on the fat cell.3 Captopril is an anti-hypertensive drug that blocks the activation of a hormone found to be present in the fat cell,52 and may decrease alpha-2 receptors.53 Liposuction is a cosmetic surgery, which can remove specific fat deposits.54

Bodybuilders will use extreme measures to achieve extreme losses of body fat. As can be seen, most of these methods carry risks and many are illegal for use without a physician's prescription. None of the methods listed above should be used without further educating oneself about the costs and risks. If such a choice is followed, accepting the possible consequences must be considered as part of the price.

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