24 Jan , 17

How Radical Diets Kill Your Testosterone

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Obesity is one of the greatest threats to healthy testosterone levels. Many, many studies have linked obesity to low testosterone levels. Excess body weight can lead to hypogonadism, with 75% of obese men suffering from low testosterone output. It makes sense that going on a diet to lose weight is a good way to restore your testosterone levels to normal.

But did you know that your diet can be just as harmful to testosterone production? If you’re not careful with the way you diet, you could end up lowering testosterone even further. Pretty scary thought, isn’t it? Below, we’ll look at how your diet may be killing your testosterone levels…

The Dangers of Crash Dieting

“Crash diets” are the name given to any diet that leads to drastic reduction in calorie consumption. The average male needs 2,000 to 2,500 calories per day, depending on their exercise levels. A crash diet is anything that restricts them to fewer than 1,200 calories per day.

Crash diets have become all the rage in the last decade or so. They’re seen as the ideal solution for those who want to lose a lot of weight in a short amount of time. After all, if you cut back for a week or two, your body will be FORCED to burn fat—leading to weight loss, right?

Oh, so terribly wrong!

Crash diets can have all sorts of terrible repercussions on your health. Anything that restricts your calorie intake severely can lead to problems like:

  • Slowed metabolism. The crash diet causes your body to shut down, as it doesn’t have enough calories to function properly. You use less energy on a daily basis, meaning your body is less efficient at processing the food you eat.
  • Weakened immune system. Your body needs more than just vitamins and minerals to fight off disease; it also needs energy to produce immune antibodies, white blood cells, and the other internal defenses. Deprive your system of nutrients and energy, and you expose your body a higher risk of infections.
  • Dehydration. Your body needs a certain amount of liquid (2-5 liters per day) in order to function properly. A lot of that liquid comes from the food you eat. However, if you go on a crash diet, you reduce the amount of food-based liquid you consume. You also retain a lot less water, as it’s rushing through your digestive system too quickly for your body to absorb. You end up peeing all the time, leading to a higher risk of dehydration.
  • Cardiac problems. Not only can crash diets have serious short-term repercussions on your heart health—causing cardiac stress, heart palpitations, and fatigue—but it actually increases your risk of heart attacks. Crash diets can also damage your blood vessels, causing cracks and tears that raise your chance of cardiac disease.
  • Weight gain. When you stop dieting and start eating “normal” again, you return to normal calorie consumption. However, the slowing of your metabolism means you have a harder time processing calories. You often end up gaining weight after a crash diet—not only a lot of the weight you lost during the diet, but more often than not EXTRA weight.

And these are just the serious side effects of crash diets! We’re not even talking about things like fatigue, headaches, vision problems, hunger pangs, bad breath, irritability, and the other side effects experienced as a result of the crash diet. As you can see, crash diets can be far worse for your body than a bit of excess weight.

Radical Diets and Your Testosterone Levels

But here’s the real kicker: crash dieting can have the opposite of the desired effect. Not only are they NOT going to lead to long-term, sustainable weight loss, but they can cause your testosterone levels to drop.

How does your radical crash diet lead to low testosterone levels?

Reduced Hormone Production – The human body uses a lot of energy throughout the day. For example, the heart uses about 10% of your daily calories just to keep beating at a steady pace. The brain consumes up to 300 calories, or 20% of your daily calories, in order to function. Things like your autonomous nervous system, your senses, your emotions, and your thoughts all require energy.

Of course, if you add movement to the day, the energy demands placed on your body increase. Standing up burns a few calories, as does walking to your car, strolling around the shopping mall, or playing with your kids. With your workout (which burns 200 to 800 calories per hour), you’re looking at easily 2,000 or more calories consumed per day.

So what happens when you don’t give your body those 2,000 calories? Your crash diet only allows you to eat 1,000 calories or so, so where does your body get those other 1,000 calories from? Initially, it taps into stored fat. However, after a day or two of this restricted calorie diet, your body realizes something isn’t right. The human body is highly adaptive, so it adapts to your new low-calorie diet by shutting down the “extra” processes—basically, anything that isn’t vital for keeping you alive. The priority is your heart, lungs, brain, and other organs. All the other internal functions get as much energy as the body can spare. In the case of a very low calorie diet, this isn’t a whole lot.

When you “starve” yourself on a crash diet, your endocrine system is one of the first to be affected. The levels of hormones like follicle-stimulating hormone, luteinizing hormone, testosterone, and growth hormone all decrease over long-term restrictive diets. The body just doesn’t have the energy to spare to keep producing hormones.

But here’s the real kicker: even when you return to “normal” eating, your endocrine function doesn’t return to normal. Not right away, at least. It can take weeks for your body to increase hormone production to your pre-diet levels. If you already had low testosterone, that can put you at a serious risk of hypogonadism. The diet, intended to promote the weight loss that would raise your testosterone, ended up lowering your testosterone even further!

Reduced Thyroid Function – Did you know that your thyroid hormones (T3 and T4) play a significant role in testosterone production? Men with hypothyroidism (reduced thyroid function) often suffer from low testosterone levels. The thyroid gland is one of the most important parts of the endocrine system, and there is a direct link between thyroid function and testosterone production.

If you’re going on a crash diet, you may end up causing severe impairment in your thyroid function. A 1979 paper found that hypocaloric diets led to a marked decrease in T3 production. As another nasty side effect, the diet also led to a reduction in metabolism.

A diet that is too restrictive can be very problematic for your thyroid gland, leading to a decrease in thyroid hormone production. Without enough thyroid hormones, your body won’t be able to produce testosterone. The result: low testosterone levels!

Increased Stress – Stress is a pretty normal part of life, considering the busy lives we lead. The body responds to stress by producing adrenaline and cortisol, which triggers the “fight, flight, or freeze” response we’re all familiar with. During these moments of stress, all other bodily functions are temporarily reduced in order for the body to focus on that “fight” or “flight”. When the stress ends, the levels of adrenaline and cortisol decrease, and the internal functions go back to normal.

But that’s the sort of stress you encounter in a life-or-death situation, or when faced with an angry drunk guy who wants to “step outside and settle it like men”. This kind of stress is short-term.

On the other hand, a radical diet puts your body under a lot of stress, and it tends to last for the duration of the diet. Chronic or long-term stress doesn’t cause a spike in your adrenaline or cortisol levels, but it will increase the production of both stress hormones. Even when the adrenaline wears off, there is still a lot more cortisol than your body is used to. Cortisol triggers the “mute” response, reducing the other internal functions in response to stress. Long-term production of cortisol (the result of chronic stress) can keep those internal functions suppressed.

Long-term cortisol production can dampen immune function, affect digestion, reduce your metabolism, and alter blood glucose regulation. And, worst of all, it can reduce the production of hormones. After all, testosterone isn’t needed for that “fight or flight” response, so it gets “muted” with the rest of the body functions.

Chronic stress is one of the risk factors in low testosterone levels. It can be caused by a busy schedule, but the anxiety of a crash diet can be just as stressful as a long day at work. Your worry over food choices, hunger pangs, eating schedules, and weight gain or loss will lead to the same cortisol production as work-related stress. The result: reduced testosterone levels.


As you can see, radical dieting is one of the worst things you can do. Not only will it NOT lead to long-term, sustainable weight loss, but it can have terrible side effects for your body. And what’s worse, it is all but guaranteed to impact your testosterone levels negatively.

The Testosterone-Friendly Weight Loss Diet

If your goal is to lose weight, you can’t just focus on your waistline. You need to think of ALL your internal functions: your metabolism, your digestive tract, your immune system, your cardiovascular system, and your endocrine system. It’s time to come up with a diet that keeps EVERYTHING healthy while promoting weight loss.

What does that diet look like?

  1. Plenty of fat. Your body needs fat in order to function. It’s used by your brain for energy, and it’s turned into hormones and cellular membranes. But did you know that a diet with sufficient fat also encourages weight loss? The fat signals to your body that you’re getting enough calories in your diet, so there’s no need to shut down and go into “starvation mode”. Even if you do cut calories (not too much, of course!), the consumption of fat—saturated, unsaturated, and even dietary cholesterol—is vital for effective weight loss.
  2. Moderate calorie restriction. Cut back too drastically, and your body (including your endocrine system) will shut down. If you scale back calorie intake by anything over 20%, you run the risk of disrupting internal functions. That’s why you should only restrict your calorie intake by 10-20%. It will take much longer to lose weight, but you won’t be starving yourself or impairing your bodily functions. This slight reduction is the key to long-term, sustainable weight loss.
  3. A proper nutrient balance. Yes, you need to get ALL the nutrients: carbs, protein, fats, vitamins, minerals, antioxidants, and fiber. Protein is the most important macronutrient, followed by fats and limited carbs. You should try to eat A LOT of veggies, some fruits, and plenty of antioxidant-rich foods. A proper balance of nutrients will keep all the internal functions running (including your endocrine system) as you lose weight.
  4. Exercise. Exercise is the “fat burning” part of your healthy diet. The food you eat gives you the energy your body needs to keep running without shutting down, but exercise is what actually activates stored fat to burn for energy. A lack of exercise can lead to moderate weight loss, but you may lose muscle mass as well as body fat. By adding exercise into the mix, you protect your muscles and keep all the burning focused on stored fat.

Wrapping Up This Section on Natural Testosterone

Maintaining your natural testosterone production is a key pillar in your the foundation of your overall health. This is particularly important for those of us who have moved into our 40’s.

Optimal health is achieved by paying close attention to the external factors, such as exercise, stress and diet which will impact our the systems that balance our hormones.

Nutrition is an important part of this process. To help guys improve and balance their testosterone levels I create the TCycle Diet. This manual outlines all of the critical processes in your body that contribute to balanced


Todd Lamb is one world's most trusted sources of Health and Fitness information and programming. He has dedicated his life to the service of others having served as a member of the Royal Canadian Regiment in the Special Service Force and as 17 year veteran Police Officer with 10 years on SWAT and 4 as a Team Leader. Todd is dedicated to transforming the lives of 1,000,000 men through honest science based information backed up with years of practical experience in Tactical Operations. Todd is a Best Selling Author of multiple best selling fitness programs and the book STAND APART

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