The fiber diet, which appeared in the 1960s in the United States, promises rapid weight loss without going hungry. Hence its immediate success. But is it really this miracle diet? How to set it up? What precautions should be taken?

It's established: a plant-centred diet offers many health and line benefits. Among other benefits, it optimizes the consumption of fiber, indigestible carbohydrates (therefore devoid of calories) present in fruits and vegetables, cereals, seeds and legumes. "Epidemiological studies show that subjects who consume the most fiber have a better weight status," says Dr Jean-Michel Lecerf, nutritionist.

There are many mechanisms by which a high-fibre diet helps to lose weight and maintain a stable weight. Foods rich in fiber are digested more slowly and require a greater chewing effort which leads to better satiety. They are also generally less caloric and, as a replacement for 'empty calories' foods, can lead to a decrease in energy intake favorable to weight loss. Not to mention their effect on the intestinal flora, an area in which we go from discovery to discovery...

Against the extra pounds, a good fiber intake is, therefore, an additional asset. "Unfortunately, the current, refined, processed and insufficiently diversified diet depletes this intake," notes Hélène Leflaive, a dietician. We consume an average of 20 g per day, instead of the recommended 30 g!'

What are the benefits of dietary fiber on the line?

A diet rich in fiber is associated with better weight status and better regulation of fat mass. Here are their different modes of action:

Fiber fills the stomach cheaply

Indigestible, fiber gives foods that contain more calorie-free volume. This is the case for fruits and, above all, vegetables with low energy density (20 to 30 calories/100 g!). By filling the food bolus, they quickly satiate.

In addition, foods high in fiber require a significant chewing effort, which can help slow down the diet and, subsequently, reduce overeating. "Starting a meal with raw vegetables is a good way to balance the meal," recommends Hélène Leflaive.

Fiber slows gastric emptying

Arriving in the stomach, soluble fiber (pectins, beta-glucans...) forms a viscous gel in contact with liquids and slows down the evacuation of its contents, especially carbohydrates.

Studies have shown that a meal containing foods rich in fiber can limit the feeling of hunger until the next meal, so snacking.

Fiber decreases the glycemic index of foods

"The richness of a food in fiber, especially soluble fiber, helps a little to lower its glycemic index (GI), that is to say its ability to raise the level of blood glucose," notes Dr. Lecerf. Thus, all vegetables have a low GI, brown rice has a GI of 50 against 70 for white rice, wholemeal bread 65 against 95 for white baguette... The presence of fiber also explains why an apple juice has a GI of 44 compared to 38 for a whole apple. With, again, a positive impact on satiety and storage.

Fiber reduces fat absorption

In the intestine, the gel formed by soluble fiber binds to some of the lipids, retains them and evacuates them in the stool. Among the fat molecules, they trap cholesterol, part of which is therefore eliminated. They thus participate in the regulation of cholesterol and have a cholesterol-lowering effect.

Fibers regulate transit

By increasing the volume of stool in case of constipation, and by capturing water in the digestive tract in case of diarrhoea, they improve intestinal transit. "You have to introduce them gradually when you are sensitive or unaccustomed to consuming them," says Hélène Leflaive.

Foods rich in fiber are also rich in nutrients

Whether it's fruits and vegetables, whole grains, legumes or seeds, increasing the share of fiber-rich foods is beneficial. "This makes it possible to optimize the intake of vitamins, minerals and antioxidants, which also have an interest in weight regulation," insists Dr Lecerf. Moreover, experiments with blind fiber supplementation have not yielded as convincing results as an increase in fiber-rich foods.

Should we eat soluble or insoluble fiber?

Both are necessary and complementary:

By forming a gel in contact with liquids, solubles (mucilages, pectins... rather present in fruits and vegetables, legumes and some cereals) slow down the assimilation of carbohydrates, decrease the absorption of fats and cholesterol and regulate transit.
As for insolubles (cellulose, lignin... in whole grains and oilseeds), they increase the volume of stool and stimulate intestinal contractions. "In a weight loss approach, solubles are more interesting and can be slightly favored," says Dr Lecerf. But you need a varied fiber intake.'

How to increase your fiber intake?

Swap the refined for the complete. Pasta, rice, bread... But also flour (T150). "To improve digestive tolerance, it is better to introduce them gradually by starting with semi-complete (T80 flour)," recommends Hélène Leflaive.

Provide fruit and/or vegetables at each meal. Goal: 5 servings (80-100 g) per day, minimum. Ideal: fruit for breakfast and lunch or dinner, raw vegetables or soup as a starter and/or vegetables cooked at the main course of lunch and dinner.

Introduce 2 to 3 servings of pulses per week. "For digestion, it is better to start with lentils, better tolerated," recommends the dietician. Other precautions: a prior soak and gentle and long cooking with a little bicarbonate.

Chew oilseeds and seeds. As a snack or in salads, preparations... Preferably with the skin, rich in fiber! No more than 25-30 g per day, as they remain very energetic.

Keep the peelings! Plants, seeds... fiber concentrate!

What are the most satiating fiber-rich foods?

Particularly rich in fiber, some foods allow you to be satiated quickly and durably without increasing the caloric bill:

Quinoa

Rich in fiber (3.8 g / 100 g cooked weight) and proteins as complete as those of meat or fish (5 g / 100 g cooked is 2 times more than rice), quinoa has a particularly low glycemic index for the family of starchy foods / cereal products: 35!

It is eaten hot or cold (in salads), always combining it with vegetables that, thanks to their volume and fiber, make it possible to reach satiety faster and to be full for longer.

Pistachio

Slightly less caloric than other oilseeds, pistachio has a high satiating power thanks to its richness in fiber (10.6 g / 100 g, with the skin), protein (18.4 g or as much as meat), and lipids (47 g). It also contains magnesium (115 mg/100 g) soothing and anti-craving.

It is eaten unsalted and with the skin, as a snack (a small handful) or at breakfast.

The apple

Well supplied with fiber (2.9 g / 100 g), it contains pectins that slow down gastric emptying and carbohydrate assimilation. In addition, the chewing effort promotes the secretion of histamine, which allows neurons to transmit a message of satiety.

It is consumed raw and with the skin, so preferably organic.

Split peas

With 128 calories, 7.95 g of fiber, 16.3 g of carbohydrates – per 100 g cooked weight – and a glycemic index of less than 30, split peas are an excellent source of sustainable energy.

They are consumed in soup or puree, having taken care to soak them (at least 24 hours) or even germinate before preparing them to improve their intestinal tolerance.

Spinach

Light (28 calories/100 g) and fibrous (3.5 g), spinach also contains in its membranes thylakoids, substances that would slow digestion and induce the secretion of satiety hormones.

They are eaten fresh in salads, but also chopped and pan-fried with garlic, or mixed or centrifuged (juice, soup) forms in which they best release the satiating active ingredients.

Coconut flour

Obtained from the grind of defatted and dried coconut flesh, coconut flour displays up to 50 g of fiber per 100 g, a moderate carbohydrate intake (10 to 20 g) and a floor glycemic index for one flour (35).

It is consumed light, it advantageously replaces ordinary wheat flour in cakes, bread... 50 g instead of 200 g.

Oatmeal

Oatmeal contains a lot of fiber (7.2 g/ 100 g), including soluble beta-glucans that, by swelling in the stomach, stall quickly and, by slowing down the assimilation of carbohydrates (glycemic index = 40), offer lasting satiety.

It is consumed 40 g in milk at breakfast; replacing some of the flour for more satiating cakes.

Fiber diet: week 1 of slimming green menus

Ready to give pride of place to fiber to finally quell hunger and lighten up without struggling? Thanks to these 14 days of menus, increase your consumption of plants without sacrificing balance and easily lose 2 to 3 kilos.

Breakfast of your choice

Option 1: Green tea, coffee or infusion without sugar + 50 g of bread (wholemeal, cereal, pumpernickel ...) + 1 egg or 1 slice of ham or 1 slice of smoked salmon + Plain yoghurt or 2 petits-suisses or 30 g of cheese + Seasonal fruit

Option 2: Green tea, coffee or infusion without sugar + 40 g of oatmeal or muesli without added sugar + 250 ml of semi-skimmed or vegetable milk or 100 g of cottage cheese + 5 to 10 almonds, walnuts, hazelnuts... + Seasonal fruit

Monday week 1

Lunch: Grated carrots vinaigrette + 120 g sautéed tofu + Grilled eggplant with basil + 30 g cereal bread + 30 g fresh goat + Watermelon

Dinner: 80 g trout fillet + 150 g brown rice + Ratatouille + Blackberries

Tuesday week 1

Lunch: Tomatoes vinaigrette + 125 g roast veal + Steamed broccoli + 150 g wholemeal pasta + Raspberries

Dinner: Summer salad: chew, melon, chives, 100 g of diced defatted ham, 100 g of wild rice + Cottage cheese

Wednesday week 1

Lunch: Raw mushrooms minced vinaigrette + 125 g of fillet of saithe in papillote Julienne of vegetables + 150 g of quinoa + 3 fresh figs

Dinner: Artichoke vinaigrette + 150 g of lentil dhal with onions and carrots + Yogurt

Thursday week 1

Lunch: Vegetable sticks with Croque + 125 g of minced steak with 5% MG + Provençal tomatoes + 2 small potatoes + Peach

Dinner: Gazpacho + 3 grilled sardines + 100 g of bulgur + Green beans + 2 petits-suisses

Friday week 1

Lunch: Pickled pepper salad + 120 g rabbit grater with herbs + 150 g wholemeal pasta + Braised chard + 3 plums

Dinner: Garden salad: grated carrots, 150 g chickpeas, red onions, lettuce + Cottage cheese

Saturday week 1

Lunch: Mixed salad: tomatoes, grated carrots, 30 g of feta, 150 g of spelt, sesame seeds, vinaigrette + Applesauce without sugar added

Dinner: Green salad vinaigrette + Sea toast: 50 g of rye bread, 30 g of fresh cheese, 2 slices of smoked salmon, lemon, chives + Peach

Sunday week 1

Lunch: Cucumber yogurt sauce + 120 g roast chicken breast + Sautéed zucchini + 150 g quinoa + 1 small bunch of grapes

Dinner: Mexican salad: 150 g of red beans, red onion, 50 g of corn, red pepper, vinaigrette + Faisselle with strawberry coulis

Fiber diets: week 2 of slimming green menus

Breakfast of your choice

Option 1: Green tea, coffee or infusion without sugar + 50 g of bread (wholemeal, cereal, pumpernickel ...) + 1 egg or 1 slice of ham or 1 slice of smoked salmon + Plain yogurt or 2 petits-suisses or 30 g of cheese + Seasonal fruit

Monday week 2

Lunch: Crunchy green beans in vinaigrette + 125 g of salmon pavé with dill 150 g of split pea puree + Pear

Dinner: Melon + 120 g of sautéed shrimp, small vegetables and 100 g of rice vermicelli sautéed in wok + Yogurt

Tuesday week 2

Lunch: Raw fennel, walnut and blue + Vegetarian spaghetti: 150 g of whole spaghetti, tomato sauce and mushrooms, 40 g of textured soy protein, 20 g of Parmesan + Pear

Dinner: Salad niçoise: tomato, 100 g of brown rice, 1 hard-boiled egg, onion, 50 g of natural tuna, vinaigrette + 3 figs

Wednesday week 2

Lunch: Grated carrots dressing + 120 g of smoked bacon fillet + 100 g of wheat + Green beans + Yogurt

Dinner: Melon + Oatmeal terrine with zucchini and cherry tomatoes + Cottage cheese

Thursday week 2

Lunch: Radish with crunch + 125 g of roasted cod back + Fennel + 150 g of brown rice + Peach

Dinner: Vegetarian salad: 100 g of lentils, 100 g of bulgur, tomato, cucumber, lettuce, vinaigrette + 2 petits-suisses

Friday week 2

Lunch: Green salad vinaigrette + Complete black wheat cake (1 egg, 1 slice of ham, 30 g of emmental) + Red fruits

Dinner: Raw beetroot raspberry vinegar + Vegetarian couscous: 100 g chickpeas, couscous vegetables, 100 g semolina, 20 g almonds + 2 petits-suisses

Saturday week 2

Lunch: 150 g of Lebanese tabbouleh + Mussels + 30 g of rye bread + Green salad + 3 plums

Dinner: Light crumble (wholemeal flour, oatmeal, sunflower seed) with seasonal vegetables and tomato coulis + Green salad dressing + Yogurt

Sunday week 2

Lunch: Cucumber yogurt sauce + 125 g roast beef + 2 potatoes + Ratatouille + Poached pear

Dinner: Split pea dhal (100 g) with carrots and onions + 50 g spelt bread + Yao