Putting on is easy if you don't intend to break all records. Breaking the record may be as hard work as working out on a daily basis to be able to go to the Olympics one day. I can't really talk about eating oneself to death in no time. However, I can talk about eating too much and growing fat slowly.
If your normal day job includes an office cubicle, an office chair and a car that drives you here and back you have actually very good chances to grow fat slowly. Making a plus of 30 kilos in 2 years is absolutely possible.
A 24-hours day (8 hours sleep, 8 hours free time, 9 to 5 office job) will cost you about 2000 kcalories if you have a BMI of 25 and you walk some 2-3 kilometers a day and your fitness is below average compared to a weekend warrior. 2000 kcalories can be compared to ~380g milk chocolate or Nutella or 4.75 liters of Coca Cola or 4 McDonald's Big Macs.
Simply put, all you need to do is to eat more energy than your body requires. For example, if your body requires 2000 kcal and you eat 2300 kcal a day, and one kilo fat has an energy equivalent of about 7000 kcal, it takes about 23 days to put on 1 kilo body fat. Eventually, it will take about 700 days to put on 30 kilos of body fat. That's just under 2 years.
Your chances of growing fat are well improved if you
- avoid walking or any other kind of physical exercise. Use your car to travel distances of 100 meters or more and don't do any sport. Your car, your couch and your TV set are your best friends.
- avoid vegetables and light fruits.
- make very regular eat-all-you-can's in McDonald's, Burger King or which fast food chain you ever prefer. Don't forget to order the super-sized Coca Cola cup as a sugar add-on.
- eat one 100g milk chocolate with nuts every day as an afternoon snack.
- never abandon your daily dessert. Order seconds if you liked it.
- eat a big mayonnaise-ham-cheese sandwich as a 10 o'clock snack. Before you start remove the tomato and the salad.
- never avoid your normal breakfast, lunch and dinner. The size of your meal matters. Eat the normal portion.
- eat pastry, cheese, french fries, ketchup and deep-fry everything that can be deep-fried.
In short, eat too much of everything. Combine carbon hydrates and fat in huge quantities and be very disciplined and persistent about your new eating stile. Whatever you're told, for example by your doctor, don't let up!