Protein-only... intermittent fasting... Which diet gets the weight off?

Protein-only... intermittent fasting... Which diet gets the weight off?

Trying out the latest dieting fads

Solange Vázquez

Friday, 29 September 2023

Opciones para compartir

Well, the summer came and went and, according to those fanciful forecasts that most of us made in spring, we should have been proudly showing off our bikini bodies for the last few weeks. After all, having selected which diet to go on (which one? just pick any that's in fashion!) and lots more exercise, nothing could go wrong. Couldn't it? So why have we just spent the summer with the curves we have always had? Reality, just like in previous years, has stomped all over our crazy notions.

We know our thinking is misguided: according to a study by the Spanish Academy of Nutrition and Dietetics, in collaboration with the Mapfre Foundation, 80% of the population believes that miracle diets are dangerous and do not work, but only 20% dare to admit that they have tried them.

But a topic like this requires, in addition to research studies, a proper, 'scientific' verification: the writer of this report, that's me, has tried two diets taken from the internet to see if they work (or not), but it is also important to have the experts comment on the small print behind these diets that is rarely discussed.

Our account of this experiment begins in May. But first a warning: do not try this at home, it is not healthy (they will explain why later). Also a spoiler alert: I have hardly lost any weight. Let's just say that, although it is up for debate, my weight is correct for my age (well into my forties), body shape (well-built, leaning towards slightly plump) and height (quite a few centimetres above the national female average). Let's get started...


  • Diet: High-protein

    Summary: Two weeks eating moderate protein (eggs, chicken, turkey, beef, fish, about 200g per portion) and only green or white vegetables (because they have fewer carbohydrates). No dairy products, no fruit, no pulses, no alcohol, no soft drinks, no sugar...
    Weight loss: 3.2 kilos in 10 days.
    Benefits: You don’t feel hungry and yes, you lose weight fast.
    The worst: No lapses allowed and you’re left feeling tired.
    The expert’s opinion: “By not consuming carbohydrates, there comes a point when the body runs out of sugar reserves and, in order to continue functioning, it creates ketone bodies to be able to use the fat we have accumulated as energy. When this situation occurs, we enter ketosis. This can cause weakness, lethargy, headaches...

The experiment began as things should: with enthusiasm, with determination, with something as unappetising as an egg white omelette accompanied by a black coffee. May the fans of this diet forgive me, but this dish didn't look good, didn't taste good and it didn't fill me with the joys of life. It made me want to go back to bed and cry over missing my usual white coffee and toast.

The rest of the day, well, I'm not hungry and I even have much more dinner than usual (a portion of turbot and a huge salad). At home, having been told about my experiment, the family make strange faces, think I'm mad and express their concerns: "If you eat like this, you'll end up gaining weight." That would be the last straw. But it seems like I can stick with it... Or maybe not?

I shouldn't have been so keen so soon. The second day reveals the harshness of my situation. I've been in a bad mood all morning, despite having added half a jar of pepper to those hellish egg whites so that at least their taste of cork soaked in a puddle is masked. My bad mood is not only influenced by the fact that this diet has ruined breakfast for me, my favourite meal of the day, it also happens that I find myself with zero energy. Am I going down with something? Well no, because the days go by with no other symptoms, but the lethargy persists. Being like this, at half throttle, makes me very angry.

On top of that, one night I dreamed that I was eating my much-missed toast (waking up was devastating). Of course, I notice that my clothes have a looser fit... And that cheers me up a little.

But, alas, the weekend arrives, which means beers and lots of food with friends. Things go downhill: we go to a biker bar, everyone orders beers and I ask for sparkling water. The bikers look shocked, as if they want to run me over with their Harley, for sure. And I'm more set in my ways and tougher than any of them.

Do I make more sacrifices over the weekend? Quite a lot. I say no to a vermouth with colleagues, no to tasting my mother-in-law's 'torrijas' and to eating delicious things on my nephew's birthday, which seems very impolite of me because they have put a lot of effort into it. So, the tenth day arrives, several unavoidable commitments pile up and... okay, I decide to leave it at this point and weigh myself to see if the sacrifices have done any good. Well yes: 3.2kg lighter, which is a lot for me. The downside is that three weeks later that loss had been reduced by half and today it is only a memory. Was it worth it? I don't think so.

Aida Monjas, nutritionist at Sabe a Vida Salud (an online business for healthy living), is understanding with me: "After all, changing a habit or custom radically makes it much harder to maintain over time. Besides, after having something forbidden, your hunger has joined up with the desire to eat. So, in effect, you sought satisfaction and pleasure for those days of deprivation... Be careful! From this point it is very easy to enter the reward-punishment loop and even develop an eating disorder. It's not worth doing these experiments, especially without supervision. Luckily it was just a few days. Had you kept this up for longer, you could have suffered from dehydration, constipation, headache, muscle cramps, and an increase in uric acid."


  • Diet: Intermittent fasting.

    Summary: One of the most common versions of this diet is to spend 16 hours fasting (drinking only water, coffee or tea) then pack your daily food intake (healthy foods, lots of fruit, vegetables, protein and pulses) into just eight hours.
    Weight loss: None. I threw in the towel on Day 1 or, to be exact, the first night.
    Benefits: You pluck up the courage to try it as it’s not very restrictive, the hours of fasting are key.
    Drawbacks: If you have a hard time dealing with an empty stomach... don’t even try this.
    Expert opinion: “When fasting, the digestive system and the hormones involved, such as insulin that sometimes does not work well due to over-saturation, will respond better as they are not working all the time. This is the ‘good’ side to fasting.”

I'll be brief, very brief. In principle I was to run with this diet for two weeks. On the first day I have breakfast later than usual, at 10am, and by that time I am starving because I have already been up and about for three hours on an empty stomach. My last meal of the day is at 6pm and watching my family eat dinner three hours later kills me. Going to bed at midnight with my stomach grumbling loudly, even worse. Impossible to sleep, so around two in the morning I get up and have a huge glass of hot milk with cookies, the best sleeping pill. Screw the experiment.

Nutritionist Aida Monjas highlights some benefits of this diet, but acknowledges that I would have been unable to stick with it: "It is not suitable for everyone, it can increase anxiety and interfere with your daily life, and it also has negative side-effects for those with certain medical conditions," says the specialist


  • Diet: No diet, just eating healthily.

    Summary: Drink one and a half litres of water per day, have three proper meals and, if you are hungry between meals, choose yoghurt or fruit. Eat whole wheat bread, about two slices a day if needed, but only for breakfast: coffee with milk and toast with mashed or stewed fruit, or toasted bread with tomato or oatmeal with fruit... Eat pulses and beans once or twice a week (two scoops), pasta on just one day, protein with a side of vegetables most days. Everything in moderate quantity, cooked with as little fat as possible. Avoid alcohol, processed meats and sugary foods, but allow yourself the occasional treat... and enjoy it! Oh, and don’t punish yourself the next day, just get back on track.
    Weight lostAlmost three kilos in three weeks.
    Expert opinion: “Losing 2 to 4kg in a month is a good average (it also depends on how much excess weight you’re carrying).”

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