Atkins diet:
This one is a low-carbohydrate diet high in saturated fats, low in fibre, and lacking essential nutrients.

Lemonade diet or master cleanse: 
A liquid-only diet, this one lacks crucial nutrients and leads to nutrient deficiencies. It mainly relies on a liquid diet of lemon juice, maple syrup, and cayenne pepper.

Cabbage soup diet:
It involves consuming large quantities of cabbage soup and a specific list of other foods for seven days. This diet is severely restrictive and nutritionally inadequate, causing muscle loss and fatigue.

Baby food diet:  
It involves incorporating baby food into an adult's daily eating routine. It requires one to substitute regular meals with baby food, leading to nutrient deficiencies. 

Blood type diet:
As the name goes, it involves eating foods depending on your blood type. It lacks a scientific basis, and the food restrictions may lead to nutritional deficiencies.

With inputs from Vidhi Chawla, dietician, and founder of Fisico Diet and Aesthetic Clinic.

Disclaimer: This information does not replace professional medical advice. Consult a qualified specialist or your physician for personalised guidance.