The Biggest Losers
Why you should NOT go on a diet as your New Year Resolution
I am overweight. Medically. My BMI has been oscillating around 30kg/m2 for decades. I pay no particular attention to what and how I eat. I fact – I love food. Genetically, I am also a super-taster, and I derive enormous spiritual satisfaction when sampling the work of the world’s greatest chefs.
Obesity is linked to hundreds of adverse health outcomes, from cardiovascular disease to cancer, metabolic disfunction, or increased risk of infections. The quality of life and longevity of people who are obese is lower than of those who typically fall in the “normal” ranges of body weight (ref, ref, ref, ref, ref, ref, ref, ref, ref, ref, ref, ref)
It is also the start of 2025. Time when people make so called “resolutions” (short term commitments that they abandon no later than by the second week of February). Personally, I don’t make “New Year Resolutions”. Instead, if anything, I tend to reflect on the past year.
In December 2022, a friend of mine (also a doctor) underwent an enormous body transformation. He has lost TONS of fat and gained a large amount of muscle mass. He has posted his results online, and they are were seriously impressive.
For most people – images of body transformation are hugely motivational. It made me envious as well. But since I am not really good at extreme sports or restrictive dieting, I decided to what I do best before committing to a rigours body transformation programme: I reviewed the evidence!
Dieting – rate of success
Believe it or not – less than 5% of people achieve a long-term weight loss from diets and/or exercise (in scientific literature “long-term success” is typically defined as ability to retain lost body weight for 2 years). 95% of all people who have successfully lost desired amount of weight through dieting, tend to regain everything they lost in a relatively short amount of time, often with a surplus (ref, ref, ref).
You probably know that I do not accept anecdotes as evidence. My friend’s success however, was so spectacular that I could not just ignore it. I have therefore decided to look for other examples of people who have managed to achieve significant reduction in body fat. Because I like to do things the easy way – I have started the review of anecdotes by… watching more TV.
In particular, I have binged on an old TV show titled “The Biggest Loser” (link).
The show is actually quite entertaining, especially if you watch it sitting on a comfy sofa. The participants voluntarily agree to be pushed hard in order to lose massive amounts of weight. They embark on aggressive dietary regimens and subscribe to heavy (daily) exercise programmes that combine ridiculous amounts of cardiovascular exercise and heavy weight lifting. Participants change most of their dietary habits. Some exercise so hard, that they vomit or pass out from exhaustion. Daily. For 30 weeks. Most of the participants are successful. Virtually all of them reshape and remodel their bodies. Amazing, entertaining and… anecdotal.
Time for some more meaningful data.
Let’s take a closer look at published evidence. Luckily, there are quite a few studies conducted on the participants of “The Biggest Loser”: Long-term observations, decent follow-ups, studies with a more systematic approach than preselected shots on the TV screen. What do the studies show?
All participants (ALL) add back large amounts of body fat, once the filming is over (ref)
Many regain ALL the weight they have lost within a year
Metabolic adaptation (decline in Basal Metabolic Rate) among successful dieters declined on average by >25% more than it should based on the reduction in their body mass alone (!)
The dramatic down-adaptation of BMR persisted for at least 6 (six!) YEARS after the show ended
Let’s think about it. Six months of extreme effort. Massive weight loss. Massive metabolic adaptation. Massive regain of body fat.
You can not outrun a doughnut…
- M. D. Zatonski
Temporary achievement at the cost of persistent loss of basal metabolic rate?
What does it mean? It means that vast majority of the show participants ended up worse than they have been before participating in the competition. Not only they regained most of their body fat, but now they need to eat 25% less (calories) to maintain their new weight. For years!
Numbers for geeks:
Average BMR for participants (males and females combined) was approx. 2500 kcal/day at the start. After 6 months of extreme diet and vigorous exercise the MBR dropped to an average of 2000 kcal/day. Average weight loss was 58 kgs. Average weigh gain after the show was…41 kg. But the reduced metabolic rate remained. In absolute numbers: average starting weight was 149kg, average weight after 30 weeks of training and diet was 90kg, average weight 5 years after the show was 132kg.
Yes, yes, there is some weight loss that persisted after 6 years… However, you are likely still unhappy to weigh >130kg, your metabolic rate is significantly lower and you are likely to continue to gain over time – because (unfortunately) the BMR drops sharply as we age… Temporary success, continued obesity afterwards, permanent (?) damage to your BMR, massively increased difficulty in future attempts to lose weight again… And things get harder as we age anyways.
Seriously… Another attempt to drop weight will be dramatically more difficult if you have “successfully” dieted before. You would now need to diet more restrictively and for longer to achieve the same results again. Seems like people are good at loosing weight, but suck at maintaining their new size.
Why? What can I do about it?
Because EVERY diet triggers your body’s adaptive self-preservation mechanisms (although please note: gradual caloric restriction may be the culprit; limited evidence shows that complete fasting may in fact increase basal metabolic rate, as long as there are sufficient fat reserves).
Body’s defence systems against dieting
Here is where my knowledge obtained during studying of medicine comes in. Living organisms are typically really good at maintaining something called homeostasis. There are numerous metabolic, neural and hormonal feedback loops and mechanisms that your body uses to ensure that certain parameters stay the same. Things like blood hormone levels, blood sugar, temperature, blood pressure, blood pH, intracellular sodium, etc. must be kept in a predefined narrow range in order for your body to function. Some of those mechanisms are extremely accurate, regardless of external environment. People can maintain a steady internal temperature of 38C in the Arctic and in the desert. And if you haven’t already guessed, you also have a mechanism that regulates how much body fat your body keeps.
You were born with a certain “pre-programmed” body-fat set point. This is genetically determined for each individual. The easiest way to think about your set point is to compare it to a thermostat (read more: Body Fat Set Point). Your genes predetermine certain amount of body fat considered as “optimal” for you (and you only). The “fat thermostat” is controlled by the size of individual fat cells. As the size of fat cells reduces (your energy storage decreases) your adipose tissue will reduce secretion of the hormone called leptin. Low leptin levels will reduce your basal metabolic rate (reduce the amount of energy going out), increase your hunger (maximise energy going in) and try to restore you to your set point. Just like a thermostat in your room – it will typically “overshoot” the set point. When you reach your optimal level of body fat, your adipocyte size will increase, leptin levels will rise, metabolic rate will slowly start to climb up, and your hunger will decline. Believe it or not, this mechanism is quite accurate! It can restore your adipocyte (fat cell) size to a nanometer of what it was previously…
There is, however, a slight problem…
Your organism has three mechanisms when dealing with “starvation” (or any other decline in energy intake):
Adaptation (to prevent further weight loss – decline in the BMR described above)
Restoration (increasing the rate of weight regain once sufficient energy supply is available – through leptin and hunger; also described above)
Prevention of future possible loss of energy stores. This happens by increasing number of fat cells in order to increase the potential of your body to store MORE energy than before (ref)
It is the prevention that is the problem. The faster you reduce your weight, and the more often you try to do it (ref) – the larger the number of fat cells that your body will additionally create. Your “thermostat” will aim to restore your adipocyte size (make you just as fat as before dieting), but also will try to prevent the loss in the future by providing you with more freshly made fat cells (ref). And yes, you will keep gaining fat as long as the the old and the new adipocytes reach their genetically pre-determined size.
This type of “starvation prevention” will happen each time when you go on a diet (with the possible exception of a complete fast), and later return to “normal eating”. Therefore each attempt to lose weight (especially when it is rapid) will likely end up badly for you. Unless you can make and keep the lifestyle change permanently, for the rest of your life*.
* Actually, since your BMR will further decline with age (see the table above), you will need to constantly decrease your energy intake to avoid fat gain.
This means that the ONLY way to permanently reduce body fat is to do either do it relatively slowly, gradually, without massive changes to your habits, while ENSURING that you can stick to your new feeding or activity patterns forever. More recent studies show that complete fast (no food intake) may increase use of energy in the short term, as long as sufficient body fat stores are available, with relatively little impact on muscle mass loss, when subjects remain physically active. Adherence (or the lack of it) is the main reason why the overall success rate of any diet plan is no greater than 5%. Adherence to fasting regimens in environments abundant with food is also questionable, and very difficult to follow for most people.
In conclusion, if your New Year Resolution is to lose weight forever, be conscious that the only way to do this, is to make a permanent change to they way you eat and move. Move more, eat less, stick to your new lifestyle forever. No magic diets. No miracles. Nothing new. Nothing you didn’t already know.
Fasting and increased fibre may help to regulate hunger, which in turn can help some individuals to eat less. This is due to the hormonal and behavioural modification induced by slower release of insulin (which instructs the body to store excess energy).
All the diets that “work” (temporarily) introduce some sort of energy restrictions (food groups, time, etc), and therefore an energy deficit. Others don’t even do that (temporary apparent weight loss is simply a result of reduced water retention due to depleting glycogen stores or limiting your sodium intake).
In other words - if you go on a diet - your failure rate is going to be around 95%. Because #science. Unless... you will be able to stick to your new feeding and exercise regiment for the rest of your life. Make sure you make small, sustainable adaptations. Ask yourself questions that matter: Can you live with never eating pasta or ice cream? Can you exercise everyday for 3 hours for the rest of your life?
Here are some examples of what will NOT work for you in the 2023 (and in any other year), unless you miraculously happen to be the person who can stick forever to those idiotic recommendations. I have listed them alphabetically, so you can easily find what will not work for you in the long run (and some that can actually kill):
Alkaline Diet
Anti-[Insert Name of Any Disease] Diet
Atkins DIet
Avoiding Swamps Diet
Beverly Hills Diet
Blood Type Diet
Carnivore Diet
Cigarette Diet
Cleanse Diet
Detox Diet
Drinking Man’s Diet (precursor to all low-carb diets)
Drinking Urine Diet
Dukan Diet
Eye Colour Diet
Graham Diet (precursor of vegetarian and vegan fads)
[Insert Any Fruit / Vegetable] Diet
[Insert Any Fruit / Vegetable] Juice Diet
[Insert Any Food] Mono-Diet
[Insert Any Name of a Celebrity] Diet
[Insert Any Product you Need to Buy] Diet
[Insert any Religion] Diet
[Insert Any Vinegar] Diet
Intermittent Fasting (although longer fast may have additional benefits for weight loss and/or longevity).
Ketogenic Diet
Liquid Diet
Low Carb Diet
Low Fat Diet
Lunar Diet (aka Werewolf Diet)
Mediterranean Diet
Negative Calorie Diet
Paleo Diet
Raw Diet
Snake Diet (seriously!)
Soup Diet
South Beach Diet
Tapeworm Diet
Zone Diet
and any other diet
Oh, and don’t believe everything you see on Instagram or TikTok – same things happen to athletes too (ref).
