At one point or another, most of us have tried dieting, whether it's cutting carbs, restricting calories, cutting fat... the list goes on.
What many people don't realise, however, is that constant yo-yo dieting, overtraining and limiting the amount of food you eat can have an effect on your body's ability to metabolise food.
That's where 'metabolic damage' comes in, which is a term thrown around a lot these days, and it certainly sounds scarier than it is.
To find out more about this phenomenon (and separate myth from fact), as well as how to fix the problem, The Huffington Post Australia spoke to two health experts.
What is metabolic damage?
"Metabolic damage', or better known as 'starvation mode', is the phenomenon referring to the body's physiological adaptation or natural response to long term calorie restriction or deficit," Robbie Clark, dietitian and sports nutritionist, told HuffPost Australia.
"This deficit can be a result of reduced calorie intake, increased calorie expenditure through exercise, or a combination of the two."
Essentially, metabolic damage (or starvation mode) can come about as a result of your body's attempt to maintain energy balance and prevent starvation.
"It is considered a natural physiological response, and is better known in the scientific community as 'adaptive thermogenesis'," Clark explained. "Starvation mode was a useful physiological response for our hunter and gatherer ancestors in order to survive, but it does more harm than good in the modern food environment where obesity is extremely prevalent and widespread."
According to body science expert Moodi Dennaoui, aka The Diet Doctor, the term 'metabolic damage' is slightly inaccurate and misleading.
"Metabolic damage is a very harsh way of describing this very delicate and intricate topic, so I'd rather call it 'metabolic adaptivity'," he told HuffPost Australia. "It also makes more sense as there are several variables that influence someone's metabolism, whether it has stagnated, why it has stagnated and how these hurdles can be overcome.
"Metabolic adaptivity typically refers to a change in one's metabolism. If we use the word 'damage' then we are discussing the negative impact various lifestyle and dietary habits can have on metabolism.
"Other variables also influence the metabolism, such as sex hormone levels, macronutrient intake (especially protein), exercise style, frequency and intensity, age, medication use, genetic predisposition, and more."
How it comes about
One main reason why metabolic damage or adaptivity can occur is when our calorie deficit is too large (that is, the energy going in is less than energy going out), which essentially tells our bodies to slow down metabolism in order to preserve energy.
"When you lose a lot of weight, the body's adaptation response is to start trying to conserve energy by reducing the number of calories you burn," Clark said.
"As a result, this can make you feel hungrier and increase food cravings. This may cause a halt in your weight loss efforts, which can make you feel unsuccessful and miserable that you abandon your weight loss efforts and gain the weight back as a result."
"The most common reason for metabolic issues that I have encountered have been due to yo-yo dieting," Dennaoui added. "By that I mean starvation type diets, fad diets, followed by long periods of over-eating and then under-eating again."
The best thing you can do to help yourself if you find yourself in this situation is to rein in the exercise.
While metabolic damage, or starvation mode, does exist, both Dennaoui and Clark said we need to be careful about how we think about this phenomenon.
"The metabolism does not physically become damaged. Your body's physiological changes, of which there are dozens, can affect the way your body and your brain interpret all these variables, hence causing a change in the metabolism which may be for the better but more commonly for the worse," Dennaoui explained.
"So, your metabolism has merely adapted to the variables that have been dictated by you. A metabolic adaptation has occurred, not damage per se."
Clark also added that more scientific evidence is needed to prove whether metabolic damage really has long term effects.
"This phenomenon is very real, but whether this response is so powerful that it can prevent you from losing weight, or even start gaining weight despite continued calorie restriction, is still not clear. More research is still needed in this area," he said.
The common signs and symptoms
As food fuels both your body and brain, being in a constant state of calorie deficit can affect your energy, mood and digestion.
"Since this phenomenon wreaks havoc on your brain, particularly the hypothalamus, signs and symptoms associated with this condition are linked to the endocrine system (hormones), immune and digestive system," Clark told HuffPost Australia.
"There are three common types of blatant signs that I like to associate with things I hear clients, friends and family say," Dennaoui said.
"One: 'I'm dieting but I don't seem to be losing weight'; Two: 'I started losing weight on this diet I'm following but it's all come to stop' and; Three: 'I started this diet that worked for me in the past but it's not working this time around and it's really frustrating me. I think I need to eat less and train more'.
According to Clark, some of the signs and symptoms to look for which suggest there is some form of metabolic dysfunction include:
- Constipation and/or diarrhoea
- Reflux or heart burn
- Low energy or fatigue
- Increased hunger and food cravings
- Reduced libido
- Oedema -- fluid retention, especially in the calves or ankles
- Anxiety and depression
- Weight gain or stubborn weight loss
- Loss of muscle mass
- Irregularity or cessation of periods in women
- Low immunity, recurring and/or prolonged colds and flu
- Sleep disturbances
- Changes in mood
What to do about it
If these symptoms are affecting your day-to-day life, it's best to see a health professional in order to help restore balance.
"Any form of endocrine dysfunction requires a medical or other health professional who can assist you back to hormone balance and optimal health," Clark said. "Depending on the severity of your hormone imbalance, as well as any biochemical dysfunction, this will determine how involved your treatment plan is."
To help out your body and metabolism, Clark and Dennaoui recommend following these tips.
1. Avoid overtraining
While it's still important to move your body on a regular basis, over-exercising may hinder your efforts.
"The best thing you can do to help yourself if you find yourself in this situation is to rein in the exercise," Clark said. "Rest and recovery is absolutely essential and if you're someone who is training five or more days a week and even twice a day, it is recommended you cut back on the metabolic conditioning and long-duration cardio.
"Reducing the intensity and duration of your training sessions will see an improvement. You may continue doing some strength training to help maintain muscle mass, which is prone to break down faster in these states."
2. Focus on a balanced, healthy diet
This doesn't mean limiting your calories or cutting out foods. Eating a variety of whole foods, and treating yourself once in a while, is important.
"The initial step in rectifying these issues is to aim towards a healthy homeostasis. By that I mean cleaning up your diet by eating more whole foods because they force your body to expend more calories through digestion, which means your metabolism is already on its way to improving," Dennaoui said.
"Diet is essential to make sure your body is getting the right macronutrients, vitamins, minerals and antioxidants to help prevent further stress on the body. A dietitian can help you formulate the right plan for you," Clark added.
3. Make de-stressing a priority
"Stress management is vital. If you have added stress from work, finances, unhealthy relationships and so on, it will add to the emotional stress on the body and create more of an imbalance," Clark said.
Engage in some stress management activities such as yoga, meditation, tai chi or even slow walks on the beach.
"Sleep is the time your body undergoes physical and mental repair," Clark said. "Make sure you are going to bed at a reasonable time and are getting a good night's sleep.
"If you are struggling in this area, it's important to let your health practitioner know."
5. Look after your gut
"Your gut health is crucial because it determines how you digest food, including the amount of energy you expend digesting it, how much of the food you eat is actually stored, and finally what your body does not need and excrete," Dennaoui said. "A healthy gut is imperative to a healthier metabolism adaptation."
Finally, to avoid metabolic damage or starvation mode to start with, Clark and Dennaoui recommend the following:
- Avoid fad diets like the plague -- they are temporary and not sustainable.
- Increase your protein intake -- protein has a high satiety so it will keep you fuller.
- Eat every three hours to encourage your body to trust that you are going to nourish it regularly, hence giving your body less of a reason to latch onto food and store it as fat.
- Avoid processed foods -- they require little digestive effort because a lot of the processes required during digestion are missing due to the fact that they are processed.
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