The Mayo diet

Particularly fashionable in the 80s, the Mayo diet is aimed at those with exceptional willpower who are capable of eating almost nothing but eggs for two weeks.

How it works
The Mayo diet is an extremely restrictive 14-day low-calorie diet: the daily ration of calories shouldn’t exceed 1000.
You have to cut out most foods: fat, sugar, starch, pulses, dairy produce and most fruit (except grapefruit). Grapefruit makes up part of the slimming plan: according to the regime it helps burn fat.
The same goes for eggs: this diet recommends 6 a day .They're high in protein, low in calories and filling.

A typical day
Breakfast: 1/2 grapefruit, 2 hard-boiled eggs, unsweetened coffee or tea, 1 rusk.
Lunch: 2 eggs (cooked without fat) or 100g of meat alternately, as many tomatoes as you like, 1/2 grapefruit, unsweetened coffee or tea.
Dinner: 2 eggs, green salad, celery, as much cucumber as you like, 1 rusk, unsweetened coffee or tea.

Results
You can lose 5 to 7 kilos in two weeks if you follow the programme scrupulously.

Plus points
It’s cheap, easy-to-follow and doesn't require much cooking! With such a low calorie intake, weight loss is significant.

Downsides
This diet is only followed for 14 days, after which it puts the metabolic system in danger because the calorie intake is insufficient for your body's needs.
Protein, calcium, potassium and vitamin deficiencies are inevitable.
This diet tires you out because your body draws its energy requirements from adipose tissues (fat) but also from muscular and bone tissues.
Eggs are rich in cholesterol which, in the long-term, harms the cardiovascular system.
You will be hungry. 
You can soon put the lost weight (or even more) back on at the end of the diet.
It could put you off eggs for a long time!

Note
It’s advisable to consult a doctor or nutritionist before starting this kind of diet.