For decades we have been told that to lose weight just eat fewer calories than you burn.
"Calories in, calories out."
Easy, isn't it?
But this equation, simple, reassuring and straightforward, is also deeply wrong, if we talk about humans and not of laboratory ovens.
What is really a calorie?
A calorie, by definition, is the amount of energy required to heat 1 gram of water of 1°C.
In the food context, we actually use the kilocalorie (kcal), that is, 1,000 calories: the amount of heat generated when you burn A food in a calorimeter.
But the human body is not an oven.
It does not "burn" food to generate heat.
It does not measure energy in kilocalories.
It does not convert 100 kcal of sugar and 100 kcal of fat in the same way.
E never behaves like a linear machine.
The body does not use heat: it uses ATP
At the cellular level, the true biological energy unit is not the calorie, but theATP (adenosine triphosphate).
It is ATP that powers your muscles, your brain, your heartbeat.
And the production of ATP depends on many factors, not just by how many "calories" you eat.
Calories are only potential energy
Take a steak or a glass of wine: On paper they could have the same caloric content.
But in the body:
- Metabolic pathways change
- Activated hormones change
- They change the tissues that will use or store that energy
Wine will raise insulin and overload the liver.
Steak will stimulate glucagon, protein synthesis and thermogenesis.
Same number of calories? Yes.
Same biological effect? Absolutely not.
The myth of energy output
"You burn more than you eat."
But how much you burn Depends on:
- The quality and composition of the food
- Your hormone profile (cortisol, insulin, androgens, thyroid...)
- Your sleep, your sunlight, your body temperature.
- Your mitochondrial efficiency
- Your digestive and absorptive capacity
- Your level of stress, inflammation, disease
- The type of movement you do (walking ≠ sprinting ≠ weights)
The body is not passive. È adaptive.
When you eat more, the body may decide to spend more (more heat, more spontaneous movement, more anabolic hormones).
When you eat less, the body can slow everything down (less thyroid, less heat, less vital drive).
This is called metabolic adaptation.
🧬 Hormones decide where energy goes
Do you want an example?
- In a state androgenic (high testosterone): calories go toward muscles and bones.
- In a state cortisol (chronic stress): the same calories can go toward visceral fat, inflammation and muscle catabolism.
📌 Same caloric "input."
📌 Opposite metabolic results.
Interesting data:
Two people eating the same amount of calories, with the same macros, can:
- gain or lose weight differently
- accumulate fat in different areas
- Change their lean mass, insulin sensitivity, mood, thermogenesis
The body doesn't add up the calories like on a calculator.
Challenges interprets them, adapts them, directs them.
Two people, one pizza - same food, different effects
Imagine two people:
- same height
- same weight
- same number of calories consumed in the day
- same pizza on the plate
But with one important difference: the physiological context:
🔹 Person A has a healthy metabolism:
- High testosterone
- Thyroid hormones in balance
- Low cortisol
- Active muscle mass
- Excellent insulin sensitivity
- Deep sleep
- Mitochondria functioning as nuclear power plants
🔹 Person B, on the other hand, is in an altered metabolic state:
- Low Testosterone
- Slowed thyroid
- Chronically high cortisol
- Systemic inflammation
- Unstable blood glucose
- Little sleep, little sunlight
- Lazy, stressed mitochondria
Person A probably:
✅ will use that pizza to replenish muscle glycogen
✅ will stimulate an anabolic spike
✅ will burn the meal quickly due to active lean mass
✅ will be back in balance in a few hours
Person B, on the other hand, could:
- cause a more pronounced glycemic surge
- Stimulate more insulin to compensate
- promote the accumulation of visceral fat
- Increase drowsiness, subsequent hunger or inflammation
The point is not to demonize food
The pizza itself, Is not "good" or "bad".
But the way in which it is assimilated, managed and addressed depends on who eats it and in what metabolic state is found.
The body does not receive food as an abstract datum. It interprets it.
And it does this through the filter of your hormonal, digestive, inflammatory, mitochondrial and nervous state.
The truth?
Calories in, calories out is like saying that the efficiency of a car depends only on how much gasoline goes in and how much comes out - ignoring the engine, the type of fuel, the oil, road conditions, e the driver.
It is a simplification useful only for nutrition labels and databases.
Not to really understand how the human body works.
What really matters?
If you want to manage energy, metabolism and body composition, look beyond the numbers:
- The quality food
- The type of nutrients (protein ≠ carbohydrates ≠ fat)
- The timing (eating at midnight ≠ eating breakfast)
- Your hormones, your sleep, your circadian rhythm
- Your mitochondrial resilience
Calories are only one of many variables. And not the most important one.
Conclusion: yes, the deficit works - but at what price?
For the avoidance of doubt, it is only fair to state this clearly:
If a person introduces less energy Than it consumes,
the body will be forced to draw on its reserves (body fat, but also muscle).
📉 This means that. Slimming down is possible even in a dysfunctional metabolic state.
But at what cost?
🔴 Yes, the unoptimized person will be able to lose weight....
But the price to pay will be high. Much higher than it seems.
In the process:
- will be more and more tired, plus hungry, plus irritable
- sleep will get worse, the thermogenesis will drop, will begin to feel constant cold
- the concentration Will decrease, the mood will drop
- will disappear the motivation, the desire to move, of socialize, of live energetically
And the longer it goes on, the more the body will slow everything down: metabolism, hormones, energy, desire.
It will be a forced march against nature.
He will lose weight, yes, But that weight won't just be fat: it will also be muscle mass And in some cases, more muscle than fat, especially if does not train And does not consume enough protein.
Then what?
Once he reaches "target weight"- (assuming he hasn't given up before) - will suffice resume eating normally To see:
- the weight rise quickly
- the body accumulate fatter than before
- hunger become more intense and uncontrollable
- the signs of satiety completely out of whack
The brain, deprived for a long time, reacts with compulsiveness and it's like could no longer stop. And very often it fails.
🟢 The "optimized" person, on the other hand...
Even with a moderate energy deficit, will be able to:
- ✅ losing mainly fat, saving the muscles
- ✅ maintain energy, mental clarity, vitality
- ✅ sleep better, regulate appetite, retain motivation
- ✅ react well to a return to a normocaloric diet, recharging the tissues instead of fattening
It is a qualitative difference, not only quantitative.
In summary?
Yes, it is possible to lose weight by "flagellating" yourself through restriction, starvation and discipline.
But it is an uphill path, which the body lives as a stress, not as an evolution.
A person can also lose 30 pounds by willpower alone, but if he loses muscles, energy and hormonal health, then he just won a battle against the scale, non-organic.
The real goal is not lose weight at all costs, but to create a body that function so well that you can lose weight easily, almost without thinking about it, and then no longer resume What he let go.
The real goal is to be well And that is what I wish for you as well.
Love,
Oliver
Who can balance my hormonal and biological equilibrium? I had previously seen Dr. Tommasi, traveling from Brescia specifically for Dr. Cristina, but I was only given an appointment with Dr. Arrigo Manuela. I didn't like her because she was rushed, and she gave me a diet that any other nutritionist in my city would have given me. The result? I didn't lose even a kilogram, but I spent 500 euros in the process.
I am currently on the Kyminasi diet, with almost total food deprivation, consuming 500/600 calories per day. I have lost 12 kg in 3 weeks. I am happy, but I know how this will end. Today your email struck me, the first one I've read after all the ones I've received in recent months. Please help me. I am 50 years old, I feel like a young girl, I jump, travel, and am dynamic and active. Last night I slept with two duvets and a hot water bottle because I was so cold. You explained very clearly now why.
Help me. Thank you, Oliver.
Excellent explanation.
Hi Oliver
Many years ago, a furious but brilliant madman had the courage to say it, albeit in the wrong way, and I'm talking about Dr. Lemme
I've followed him for many, many years, and so have tens of thousands of other people.
He wrote a surreal book titled “The Man Who Whispered to Fat People.” .
Since then, I've learned what you also write, and I fight against the bead-counting of calories, which surely fuels behavioral disorders!!!
Warm greetings and thank you
Good morning Oliver, thank you so much for the healthy information you and your mother provide. In fact, I'd add that thanks to you both, I've understood and am learning so much over the past two years. Truly, thank you from the bottom of my heart. I wish you a good day and a warm greeting to Dr. Tomasi.
I agree
Thank you Oliver,
Very interesting and well-explained article.
Fundamental concepts that, if well understood, can make a difference.
You always learn something new, you and your mother are doing a great job of raising awareness.
Thank you!
Good morning. I've been following the low-carb diet for a year now and continue to do so with my wife. We immediately lost the weight we needed to lose and then stabilized. Our blood work is good, except for LDL cholesterol, which is a bit high, but our doctor says it's fine. I will continue to follow you. .
Thank you truly from the bottom of my heart for everything I'm learning. Everything written there is true. I'm learning more and more and feeling better every day. I agree because I experience it in my body every day. .
Thank you Oliver, in simple but not trivial words, you explained and clarified many “whys” that we sometimes ask ourselves!!!
Very interesting article, concepts explained well
Thank you for everything you do.
A hug
Margherita (Trento)
This article is very useful. Thank you. I will have my daughter read it too. How can I find and read other articles? Thank you.
Thank you very much, I will also have my daughter read this article. Where can I find other articles? Thank you
I actually believe that the solution isn't just caloric deficit. In fact, I'm waiting for the test results because my gynecologist and I have decided to start hormone replacement therapy. I hope that, combined with a proper diet and lifestyle, it will help resolve many of the issues caused by menopause.
Now with her, I eat more, I'm not stressed, I'm losing weight, and I'm always warm, but I've spent my life on restrictive diets with bad moods and little weight loss, and always feeling cold.
So I understand very well from this article what it means
Thank you, doctor, for your advice!
Masterclass Oliver
Thank you very much, Oliver, truly interesting.
I've been following your mom for two years and my life has changed for the better. You are fantastic!
Thank you and have a good Saturday
Dear Doctor, after falling last year and sustaining fractures in L1 and T12, I discovered I have severe osteoporosis with a T-score of -5.5. I am 60 years old, 6 kilograms overweight, and went through menopause at 44. What should I do? Please help me, thank you.
Very interesting, I'll reread it to better absorb everything. I appreciate these mini-lessons, they are very useful for someone like me who needs to understand while following a path that helps me improve my health. Very useful to delve deeper and do so with understandable language that doesn't push away but welcomes.
Thank you very much for all the advice you give me. I'm a 52-year-old lady with no health problems, thank God, but I must say that in the year and a half I've been following your advice and insights, I feel really good and on top of everything in my daily life (I'm a gardener). I've lost 10 kg anyway, even though my goal was to feel well and not gain weight since I went through menopause 3 years ago. I'm 172 cm tall and weigh 59 kg now. Thanks again.
Thank you Oliver, you were clear and explained the concept of calories very well, and how they can act differently in different bodies. Thank you for your time.
Insightful article! I'm person B, or the "unoptimized" one. I've been struggling for about 10 years to lose 22 lbs (10 kg) I gained, but nothing has worked. I've tried dozens of diets, seen different professionals, but nothing. The weight just stays there. I'd pay a fortune to get back my physical shape and health. Therefore, should I not focus on grams of meat, fish, or bread, but on something else, and then optimize everything? If you're willing to answer, I'd be grateful! Congratulations on your professionalism.
Thank you, Oliver. Always insightful! In a change process, all those intending to make it should clearly know their starting physical condition to coherently achieve the desired result.
Thank you, you were very clear! In these years that I've been following your mom (who is fantastic), I understood that we don't care about calories, and in fact, we never looked at them. But explained like this, it's very clear. While I'm at it, I also want to compliment you on your other articles; they are very useful, clear, and simple. .
Have a nice day
Lucia
Fantastic article....... thank you very much 👏👏👏👏👍
I'm starting to understand Dr. Tomasi's theories. I'm wondering what tests we can use to evaluate if our kidneys can handle a diet so rich in animal protein and red meat. Recent nutrition protocols recommend little red meat (100-200 grams per week), and especially fish (Dr. Berrino and Dr. Longo).
For the rest, I agree with the other indications.
Thank you for the very clear explanation. I've been following you for a long time, and a good portion of things were already clear, but one never stops learning.
Thank you, Doctor. I am 60 years old and have been on a diet since I was a child. The result: I now weigh 84 kg and every day is a struggle. I've always been frustrated and sad. For over a year, I've been taking anti-inflammatories almost daily for the pain caused by a faulty prosthesis that has been replaced three times. Unfortunately, I still can't be active. Would you recommend a supplement that could help me? Thank you so much.
Good day, everything is clear and scientifically okay.
I think I am ex. B.
I am 69 years old and have been retired for 1 year, and I have: gastric reflux, hypothyroidism, and I had TIAs years ago. My test results are okay, everything is fine except for a bit of LDL. It's high at 1.58, my weight is 59kg. I do Pilates twice a week and walk 5km a day. I am still active, study, and socialize.
How to lose 5 kg.
Best regards
Rita De Pace
r.depace@libero.it
Oliver, you are truly great! Your insights are interesting, exhaustive, and easy to read...accessible to everyone. Congratulations.
Francesca
Very interesting
I believe all of this is profoundly true.
Dear Oliver, so what do you need to do to know if your body is well from every point of view?
Hormone tests? General blood tests?
Thank you very much
Elda
I fully agree with everything. I'm on an anti-inflammatory journey with a nutritionist and I feel reborn. My goal is the overall health of my body and brain. I'm experiencing the benefits of gentle physical activity (Pilates) myself and have achieved excellent results. I hope that finally each of us can find the right path to live well and be healthy.
Hello Oliver, what you say is all true. I'm 68 years old and I've been on diets since I was 14. I've definitely messed up my body and my gut, but I keep making mistakes even though I'm following Dr. Tomasi's low-carb approach in my own way. I don't know what to do anymore; maybe I need a professional who understands me, or perhaps I'm the one who can't be consistent. I always follow you with affection, Anna.
Thank you, Oliver, for an excellent and comprehensive explanation! I hope it will be understood by all those people who are still stubbornly convinced that calorie counting is fundamental for weight loss and the proper functioning of the body!
How do I know if I have high cortisol, chronic inflammation, and insulin resistance?
Thank you
Hello Oliver, what you say is true. I am 68 years old and have been on diets since I was 14. I have ruined my body and my gut. I always follow your advice, but I can't be consistent. I probably need a professional. In April, I bought the "Top Low Carb" program which I am following, but I am not consistent and I get confused. As Dr. Tomasi says, be the protagonist of your own health. With affection, Anna. .
I read the PHOTO OF MY STATE 🤦🏾♀️🤦🏾♀️🤦🏾♀️🤦🏾♀️🤦🏾♀️
Excellent analysis, congratulations to you Oliver and your wonderful family.
A hug to your dear mom.
Very interesting! How do you stay well? Thank you, Laura
Thank you for these explanations. It's still hard to lose weight! Any path involves sacrifice and great motivation.
Your articles are always very interesting. Science evolves, and so do we, thanks to you!
Beautiful explanation, thank you Oliver
Good morning. Doctor, I always follow everything. I am particularly interested in reading this email today regarding weight loss, which unfortunately I can no longer achieve, and I try and try with great difficulty. I have significant problems with my legs now, also pain due to weight gain. Diet alone is not enough. I would like to do something more; pharmacological help is definitely needed. I would very much like your diagnosis so I can understand better and be well monitored. .
Confident of your attention, I await your reply.
Greetings. .
Bravo, nice clear article with many examples.
Thank you Oliver... for this very important information... a light in the scientific darkness where calories are considered the predominant factor for weight loss...
Hello Oliver, thank you for sending me this important information, and I fully agree with you. Unfortunately, due to various allergy problems, especially nickel and histamine, I had to completely eliminate fruits and vegetables. For lunch, I eat eggs, and for dinner, I eat either beef or veal. Unfortunately, I don't like cooking with ghee, so I cook my eggs with a little coconut oil because, unfortunately, olive oil causes dermatitis on my palms.
Thank you for the clarifications, which are fundamental to understanding how to approach a healthy diet correctly from a perspective different from the one we have always been accustomed to.
Good morning, Doctor
I fully agree, congratulations. Unfortunately, I have experienced what you are saying.
My daughter Olimpia, 12 years old, 1.65 tall, current weight 83 in the morning while wearing cotton pajamas, before breakfast—I can’t seem to get her to lose weight anymore… She’s had a double malformation since birth on her left kidney, which is now functioning at 30%…I can’t get her to lose weight anymore—not because of her medical conditions, which are important anyway, but for her own sake. She’s tired, listless, and very withdrawn… I need help, but I don’t know what else to do… The diets they keep pushing on me are devastating, and I’ve had enough…
Thank you for any help you can give us.
Oliver, I like the way you explain things, thank you!
You are a beautiful family! Yesterday I was in Bologna and while listening to Doctor Ruatti explain the phenomenon of light, I thought of you. You have the same way of speaking and explaining.
You've captured Grandma Tomasi's sweetness and pride! Congratulations!
I was there yesterday in Bologna!
You are fantastic and I loved you all!
Thank you very much because your newsletter is easy to understand, even for someone ignorant in the subject!
Please don't be upset with me, but my favorite remains always and forever Dr. Tomasi!!
With all the affection I have!
Eva
Thank you very much for the information... very clear and comprehensive.
Good day
Following Dr. Cristina Tomasi, I find the same expertise in her explanations. Will it be a family gift, epigenetics, contamination, conviction... Thank you, I will follow with interest. .
I follow Dr. Cristina Tomasi with great interest, and now I'll follow you too.
The picture is very clear and I agree with everything. As early as the 1990s, I had challenged the use of calories to assess the quantity and quality of meals related to a person's profession, age, and sex. You have clarified how values related to the type and health status of a human being should be calculated. THANK YOU
So what? What's the solution? Me, person B, living under the constant dominance of cortisol, what should I do? Shoot myself? In this century full of nutrition gurus who live off posts, newsletters, Instagram, and videos... with no real contact.
I look forward to your reply. Regards
Hello Oliver, I am a woman on the verge of 60. As long as I can remember, I've been yo-yoing with my weight. I'm 1.60 cm tall, and last January I reached 105 kg. I could no longer move; I even had trouble washing myself. That's when I got scared, and with the help of some supplements and eliminating sugars (mainly carbohydrates), I lost 18 kg. Now I can't seem to lose any more weight (for about 2 months now), and if I happen to occasionally eat pasta, I gain up to 2 kg, and it takes me a week to lose it again. What advice can you give me?
Thank you very much
Sincerely, Antonella
Very interesting, the system is highlighted well, making one reflect on the type of eating. However, in my opinion, quantity is always important. Also, one is not always in perfect health, so what happens then.
Beautiful article! Congratulations indeed!
It was a pleasure seeing and meeting you in Riva del Garda 😀
Very interesting and, for now, very true for me: I am improving my lifestyle, schedule, sleep, exercise, and low-carb diet, and I've lost about ten pounds. My very low HDL, which was the reason for my decision alongside Dr. Tomasi's advice, is also slowly improving. Thank you, I'll continue and hope to avoid statins. I'm following you.
Very interesting and for now very true for me: I am improving my lifestyle, schedule, sleep, exercise, low-carb diet, and I have lost about ten kilos. My very low HDL, which was the reason for my decision along with Dr. Tomasi's advice, is also slowly improving. Thank you, I will continue and I hope to avoid statins. I'm following you.
Dear Oliver,
I'll take this opportunity to compliment you. Your in-depth analyses are very interesting and useful.
Thank you for this work you do for all of us.
Cristiana
Thank you, Oliver. Your explanations are very clear. I followed you when you talked about your training experiences (even your prolonged fasting!!). .
You will become a special doctor.
With affection, Dinatella
Thank you
Complete and very clear analysis, thank you Oliver!!
Hi Oliver, thank you for this information, which your mom also promotes very well. I've learned a lot and I'm trying to put it into practice every day. Since I'm in perimenopause, there was a step I was missing: the drop in progesterone. I don't know how to supplement, could I have some advice?
Very interesting! Thank you!
Big Oliver
Good morning, Dr. Tommasi, I need to discuss a situation with you.
How can I do that?
Thank you and have a great day
Congratulations Oliver, explained perfectly... thanks a lot☺
Very nice style and excellent content, nothing at all we need : D.
I've spent the last few years trying to find the right diet to lose weight, and I still haven't succeeded. I have Hashimoto's thyroiditis and my cortisol is shot, not to mention that every time I eat carbohydrates, no matter what kind, my weight goes up and my hunger becomes unmanageable. I'm 45 years old and I'm desperate. I go to the gym 3 times a week and only do weight training, but my weight is stable. I really want to find a solution.
Thank you
Debora Marzullo
This article is complete, interesting, and deserves much reflection!!
Thank you Oliver
With affection
Barbara
Thank you Oliver!!!
Clearer than water!!! I will gladly share this of yours with many friends who have been struggling with.scales for years!!!
Looking forward to reading more of your content, a big THANK YOU!!!