A caloric restriction diet has been one of the most popular ways to try to lose weight for the past several decades. But are caloric restrictions effective in helping you shed extra pounds and keep them off?
A recent study published by Ipsos in early 2021 found that 45% of people worldwide were trying to lose weight. Just over half said that they’d exercise more and eat more healthily. But 44% of people trying to lose weight were reducing their food intake. In addition, they found that 62% of people felt that lowering their sugar intake would help their weight loss. But 41% of people globally were using caloric restrictions. Caloric restrictions were more prevalent in China, India, Malaysia, Saudi Arabia, and the USA, where 50% of people stated they were trying this method to lose weight.
But before you go hunting for caloric restriction diet plan recipes, you should ask yourself whether it’s worth following a low calorie diet plan. To answer this, you need to understand how our bodies use energy.
We don't burn calories in our bodies.
Instead, we convert the chemical energy in food into other forms of energy called adenosine triphosphate (ATP), FADH2, NADH, and heat.
Why "eat less, exercise more" is disastrous and insensitive advice.
Why is the distinction between calories, ATP and other forms of energy so important?
Let’s start by reviewing some of the science.
What is a calorie anyway?
The definition of a calorie is the amount of heat needed to raise the temp of one gram of water by 1°C. That’s all it is. Simples.
Inside your body, some of the energy in your food is used to provide heat so that you can maintain your body temperature at a steady level — usually 36-37.4°C. So this does involve using calories to produce heat. Although the mechanisms behind this are pretty complex, finely tuned, and can be dialled up and down within milliseconds.
I’m still unconvinced a physicist would agree that we can extrapolate the word calorie to incorporate thermogenesis (or the production of heat in our bodies). After all, we’re made of bones, flesh, organs, blood and the fluid between cells that we are heating up – not pure water. And it takes a different amount of heat to raise the temperature of bone by 1℃ than it does for water.
But most operations inside and outside your cells don’t involve burning calories. Instead, they’re fuelled by ATP.
What is ATP?
ATP is known as our universal energy currency because all of our cells can use it to fuel their activities. Rather than calories, ATP is also the form of energy most often used by our cells. Most of our ATP is produced in our mitochondria, tiny organelles living inside our cells. Mitochondria are often called the powerhouses of the cells because they provide most of the energy our cells need to function.
Cells contain varying numbers of mitochondria depending on their function. And the mitochondria housed within different cells can have radically different structures that enable them to optimise their performance in different specialised cell types.
Which cells expend the most energy because they contain the most mitochondria?
Your heart needs to pump your blood around your lungs and the rest of your body without ever failing for more than a couple of seconds every single day of your life. And it needs to be responsive to all the different demands you could ever place on it. Like the intense exertion required to sprint, lift heavy things, wrestle or fight for your life.
That means it needs a lot of spare capacity you don’t need to access in your everyday life. But it still needs to be able to work much harder (beat harder and faster) in emergency situations.
The brain, liver, and kidneys are also extremely mitochondrial-dense organs as they have very high metabolic rates to allow them to perform a range of critical functions. In fact, pound for pound, your brain uses more energy than any other organ daily. The average man in the UK now weighs 83.9 kg. So despite only accounting for about 1.6% of average body weight, an adult brain uses 20% of our energy.
Muscle cells are another type of cell with high numbers of mitochondria. And it’s possible to increase or decrease the number of muscle cells and the number of mitochondria within those cells by altering your activity levels and nutrition. In fact, it’s hard to think of another type of tissue that can change in size as much as muscle and fat tissues can.
So you can see that your energy use depends greatly on the activity of cells found in different tissues. And using your muscles more will require you to convert more energy from macronutrients (fats, carbs, and proteins — we’ll ignore alcohol for the moment) into ATP.
But mitochondrial health is crucial for the process of converting macronutrients into ATP.
Well-functioning mitochondria are incredibly efficient at breaking down macronutrients and churning out ATP as fast as you can use it. This is why healthy people feel so… well, healthy.
When you have healthy mitochondria, you’re bouncing with energy and optimism. You feel strong, stress rolls off your back like water from a new Teflon pan, and you’re resilient to whatever life hurls your way. With healthy mitochondria, you’ll also notice that you seldom, if ever, suffer from infections, and you certainly have no chronic illnesses. There are no mystery aches, pains or headaches either. Your head is clear; it’s a cinch for you to focus and make decisions; you’re not anxious, moody or depressed. Plus, your digestion is smooth and works like clockwork. You’re that unicorn who’s the envy of everyone around you with your slim, toned build, clear, glowing skin, and luxurious hair.
What is mitochondrial dysfunction?
Mitochondrial dysfunction is the opposite of all that. And it’s miserable.
When your mitochondria are dysfunctional, they have reduced capacity to perform all of their functions. That includes a reduced ability to convert those macronutrients into ATP, leaving your cells with an energy debt.
Your mitochondria are what keep your cells alive. There aren’t many cells in your body without mitochondria. In reality, only mature red blood cells lack them. But their lifespan is only about 120 days as a result. They can’t produce enough energy to keep repairing themselves indefinitely. And red blood cells are little more than sacks that hold haemoglobin and get swept around in the current of your cardiovascular system. As a result, their metabolic needs are low.
Healthy mitochondria in an optimal density are a necessity rather than a luxury for cells with much greater complexity and energy requirements.
Why is mitochondrial dysfunction such a big deal?
Unfortunately, mitochondria are vulnerable to damage from many sources. Toxicity, stress, malnutrition, sleep deprivation, and inflammation are just a few of the things that can harm your mitochondria. And specific gene mutations predispose you to mitochondrial dysfunction. Nevertheless, our cells can cope with a small proportion of our mitochondria being damaged at any time. The important thing is that most of the mitochondria within our cells keep functioning well. So they can pick up the slack.
However, the last thing your cells need is for most of your mitochondria to fail simultaneously. That would be catastrophic. So there are all sorts of checks and balances to prevent this from happening.
So these nutrients will remain circulating in your blood for longer. If large numbers of your cells contain high numbers of dysfunctional mitochondria, the levels of these macronutrients in your bloodstream will increase. As a result, you’ll notice elevated levels of sugar, certain amino acids and fats in your blood. Since fats are usually transported in lipoproteins as triglycerides, you’ll find that your lipid panel will show increased triglycerides.
You may also notice that your LDL increases as your thyroid gland gets roped into reducing your metabolic rate as well. Because an underactive thyroid reduces your uptake of LDL from the blood, leaving it circulating for longer than it would in a person with an optimally functioning thyroid.
High blood glucose with elevated triglycerides is the hallmark of insulin resistance. And if your mitochondrial health doesn’t get turned around, this will progress into type 2 diabetes at some point.
Usually, the most active cells with the greatest number of mitochondria are affected by mitochondrial dysfunction first. That’s the heart, liver, kidneys and brain/nervous systems. But other organs will also be affected, including the gut, skin, immune system, and hormonal organs.
Common unpleasant symptoms of caloric restrictions are mediated by mitochondrial dysfunction
So symptoms of mitochondrial dysfunction will often appear to be vague and multi-systemic. But most people will notice fatigue, mood changes, irritability, disrupted sleep patterns, aches and pains, and digestive issues.
And when you get really run down, you’ll often find you pick up whatever virus is going around, whether that’s colds, flu, or tummy bugs. For example, you could end up with a urinary tract infection. Or, if you don’t pick a new infection up, a herpes infection like a cold sore, shingles, or genital herpes will reawaken. Many other chronic and acute infections become harder to clear when you have mitochondrial dysfunction. And infections can also contribute to worsening mitochondrial dysfunction, making it harder to recover.
Meanwhile, most excess energy floating around your bloodstream in the form of glucose and fats will usually get taken up by fat cells for storage — waste not, want not. With their lower metabolic rates, the mitochondria in adipose cells can generally cope with storing fat while insulin resistant even though more metabolically active cells are struggling and rejecting energy. So even though many cells in tissues with high metabolic rates have an ATP deficit and are finding it hard to function optimally because of it, much of the energy that’s denied entry to those cells will manage to be mopped up and stored as fat. And not just in adipose cells either. You may find fat globules appearing in muscle and liver cells too.
Of course, this translates into weight gain from a reduced metabolism.
And with dysfunctional mitochondria, hypothyroidism and possibly some dysautonomia leading to poor body temperature control, you may convert less energy to heat, so your body temperature may fall. And you’ll also find that from precisely the same meal and portion size of food, a metabolically healthy person will convert more energy to heat than a person with mitochondrial dysfunction. But on top of this, a metabolically healthy person will convert more chemical energy from food or fat and glycogen stores into ATP than a person with damaged mitochondria. And it’s not because they’re more active. It’s simply because a healthy person’s mitochondria are functioning how they’re supposed to, and there are no brakes on their metabolism.
If you need further proof that "a calorie is a calorie" is a myth, let's consider cachexia.
You might be familiar with cachexia as a symptom of cancer. But you can find it with many other conditions, including beriberi (severe thiamine deficiency). And this rapid weight loss with fat and muscle wasting is a shockingly common complaint among people who contact me with gadolinium toxicity. If you’d like to read more about the symptoms of gadolinium toxicity, I’ve written about them here and here. And I’ve also written about the psychological effects of suffering from an adverse reaction to gadolinium contrast here. Despite a voracious appetite and a fear of losing more weight leading to eating massive amounts of food calories, the pounds continue to drop off them. Finally, they end up gaunt and emaciated.
Increasing their intake of carbohydrate-rich foods doesn’t abate their weight loss. But changing to a real-food, high-protein, low-carb, high-fat, or even ketogenic diet usually will arrest it. Perhaps treating them for severe thiamine deficiency at the same time might yield even better results. If they can tolerate the refeeding syndrome that would likely cause.
Recall how the energy rejected by cells is mopped up by fat cells and stored as adipose tissue in obese and overweight people. In people with cachexia, the mitochondrial dysfunction becomes so universal that even their fat cells cannot store fat, although they can break it down and release it into the bloodstream under the governance of stress hormones. In addition, there seems to be a shift from the mitochondrial production of ATP to other, far less efficient mechanisms. These processes include glycolysis of sugar, fermentation of amino acids, and oxidation of fats. In many ways, cachexia resembles dry beriberi, a vitamin B1 deficiency.
Isn’t it fascinating that mitochondrial dysfunction can result in 2 very different body shapes? You can develop overweight and obesity or underweight with cachexia. And people with every imaginable body shape can also suffer from mitochondrial dysfunction.
And if that doesn't convince you that counting calories is an exercise in futility, how about this?
You can make vastly different amounts of ATP from 1 molecule of glucose depending on which pathways you use to break the glucose down to release energy.
If the glucose can be metabolised normally using aerobic respiration (which means the energy is converted in the presence of oxygen), you can make between 36 and 38 molecules of ATP from a single glucose molecule. You might be familiar with aerobic exercise. Aerobic exercise is also called cardio. Any type of activity that you can perform for sustained periods uses aerobic respiration. And so do most of the cells in your body.
Compare this to anaerobic respiration. Anaerobic respiration is the transformation of macronutrients into ATP without using oxygen. For example, when you perform high-intensity exercise, your muscles respire anaerobically. But you can only sustain activity at this intensity for short periods because, without oxygen, lactic acid builds up in your muscles. The acid causes burning pain, which causes you to stop or slow down to recover. This is where you “feel the burn.”
During anaerobic respiration, your conversion of glucose to ATP is inefficient compared to aerobic respiration. So instead of knocking out 36-38 molecules of ATP during aerobic respiration, you’ll directly make only 2 molecules of ATP during glycolysis using anaerobic respiration.
I hope this has given you something to ruminate on. There’s plenty of evidence that inside your body, caloric restrictions don’t work how you’ve been told. But does that mean that a calorie-restricted diet won’t help you get rid of those love handles? Not necessarily. But we should discuss some more studies on the impact of caloric restriction diet plans on your health.
In other words, in practical terms, what adverse effects could caloric restrictions have on your health? We’ll discuss that in the next posts. For a deeper dive into the spine-chilling effects of calorie restriction on your mental health, read this post.