Skipping meals, avoiding starchy foods, low-calorie diets... We untangle the facts from the lies about weight loss

Between trendy diets and conflicting nutritional advice, it's becoming difficult to navigate. Promises of quick results, miracle solutions: the prevailing narrative often ends up discouraging, even creating a conflictual relationship with one's own body.

Sustainable weight loss is not actually based on extreme deprivation or excessive effort, demonstrates Sandra Ferreira, dietitian-nutritionist and author of "90 Days to Hack Your Metabolism" (Eds Vuibert).

According to her, the key lies in understanding this set of chemical processes responsible for transforming food into energy and ensuring the proper functioning of our cells.

"Metabolism is influenced by many factors, such as sleep, hydration, stress, and gut health. Losing weight isn't simply about eating less or exercising more ," she emphasizes. "It's essential to act on all the aspects that regulate this 'internal machine'."

Thus, insufficient sleep disrupts the hormones that regulate hunger, increasing appetite and complicating weight loss. In addition, poor hydration slows vital functions, including metabolism, thus reducing energy expenditure.

Finally, chronic stress elevates cortisol levels, a hormone that promotes fat storage and stimulates cravings for fatty and sugary foods. "Added to this are many preconceived notions about what makes you gain or lose weight, which hinders your efforts."

With nearly 10 million French people affected by obesity and ultra-processed foods invading our plates, it is becoming urgent to rethink our relationship with health with a more lucid and caring approach.

1. Diets make you lose weight: false

When someone is put on a low-calorie diet, they actually lose weight because by consuming fewer calories than the body needs, it draws on its reserves.

However, diets carry many misconceptions: "Between 80 and 90% of people who follow a weight-loss diet manage to lose weight... but only at the beginning. Unfortunately, according to studies, around 80 to 95% of them regain the lost weight, or even more, within two to five years after stopping the diet," explains Sandra Ferreira.

The same goes for "special diet" ready meals: these boxes, which contain all the meals of the day and promise rapid weight loss, are very low in calories (800 to 1,200 kcal per day, while a woman, for example, needs around 2,000 kcal).

"They therefore place the body in a situation of undernourishment, with a high risk of rapid weight regain. The faster the weight loss, the more muscle mass it affects, which increases the risk of quickly regaining the lost kilos afterwards."

2. Skipping meals promotes weight loss: false

This habit can unbalance the diet, cause cravings and lead to an increase in the amount consumed at the next meal.

Several studies have shown that this deprivation leads to a form of compensation: the body, deprived of energy, demands more food afterwards, thus canceling out the expected effect.

Furthermore, this practice is perceived as stress by the body, which causes an increase in the secretion of cortisol, the stress hormone, known to promote the storage of fat in the abdominal area.

"The body doesn't seek to punish; it simply reacts to what it perceives as an abnormality. Its primary objective is, above all, to ensure survival."

3. Avoid starchy foods at dinner to limit calories: false

Cutting out starchy foods at dinner is a common recommendation in many diets, but this strategy doesn't work in the long term. Starchy foods—like pasta, rice, bread, quinoa, or legumes—provide essential carbohydrates for the body.

"Contrary to popular belief, they are no more caloric than protein and play a key role in providing energy and a feeling of satiety. Eliminating them can lead to cravings, a slower metabolism, and an unbalanced diet."

And contrary to popular belief, eating starchy foods in the evening doesn't interfere with sleep. "They contain tryptophan, an amino acid that promotes relaxation and quality sleep. The key is to consume them in appropriate amounts, without excess."

4. You must remove fat from your diet to lose weight: false

Long accused of being the enemy of the figure, fats have been banned from many weight-loss diets. In reality, completely eliminating butter, oil, whole-fat dairy products, or fatty meats is neither healthy nor effective.

"Our bodies need lipids to function: they help build cells, produce hormones, absorb essential vitamins, and protect organs. Cutting them out risks deficiencies and slowing down your metabolism."

Studies even show that low-fat diets don't produce better long-term results than those that include quality fats, such as omega-3s (oily fish, flaxseeds) or omega-9s (olive oil, almonds, duck fat). "These good fats promote satiety, support metabolism, and limit weight gain."

The key? "Prioritize good fats, in reasonable quantities, without ever completely eliminating this group of foods essential to health."

5. Lemon and pineapple don't burn fat: true

Lemon does not directly burn fat. While this citrus fruit has shown effects on fat in the laboratory, it does not have the same impact in the human body.

"Drinking lemon water mainly helps you stay hydrated, which supports your metabolism and reduces hunger. The same goes for pineapple, whose bromelain helps digest protein, but doesn't make you lose weight."

6. Chocolate makes you fat: true and false

Chocolate isn't particularly fattening, especially if it's classic dark or milk chocolate. On the other hand, white or filled chocolates are much higher in calories.

"A small square of chocolate (5g) provides around 28 kcal, the equivalent of half a tomato. Consumed in moderation (2 to 3 squares per day), it therefore has no significant impact on weight."

7. Breakfast is essential: false

Often touted as "the most important meal of the day," breakfast is the subject of many recommendations. Ideally, it combines a dairy product, a source of whole grains, a piece of fruit or unsweetened compote, and a drink to hydrate.

But does that mean you have to eat at all costs as soon as you wake up? "No. If you're not hungry, it's better to wait and have a light snack for mid-morning in case you get hungry (a piece of fruit, a handful of almonds, or a low-sugar cereal bar)."

The lack of hunger upon waking can also be explained by hormones. "Leptin, the satiety hormone, remains elevated after a night's sleep, which can curb the desire to eat when you get up."