"Eat food. Not too much. Mostly plants."
— Michael Pollan (In Defense of Food: An Eater's Manifesto)

"The individual who says it is not possible should move out of the way of those doing it."
— Tricia Cunningham

"No one wakes up in the morning and says, 'I want to gain 150 pounds and I will start right now!'"
— Tricia Cunningham (The Reverse Diet: Lose 20, 50, 100 Pounds or More by Eating Dinner for Breakfast and Breakfast for Dinner)

"I am a better person when I have less on my plate."
— Elizabeth Gilbert (Eat, Pray, Love: One Woman's Search for Everything Across Italy, India and Indonesia)

"She'd even violated the only sensible rule of dieting she'd ever run across, the sage advice of the Muppets' Miss Piggy, who recommended never eating anything bigger than your head."
— Susan Donovan (He Loves Lucy)

"Tout est question d'équilibre"
— Mireille Guiliano

"Inspiration is external and motivation is internal. It is up to me to provide the switch and you to flip it on!"
— Tricia Cunningham (The Reverse Diet: Lose 20, 50, 100 Pounds or More by Eating Dinner for Breakfast and Breakfast for Dinner)

"If I don't eat junk, I don't gain weight."
— Paula Christensen

"Food is an important part of a balanced diet."
— Fran Lebowitz

"But carbon 13 [the carbon from corn] doesn't lie, and researchers who have compared the isotopes in the flesh or hair of Americans to those in the same tissues of Mexicans report that it is now we in the North who are the true people of corn.... Compared to us, Mexicans today consume a far more varied carbon diet: the animals they eat still eat grass (until recently, Mexicans regarded feeding corn to livestock as a sacrilege); much of their protein comes from legumes; and they still sweeten their beverages with cane sugar.
So that's us: processed corn, walking."
— Michael Pollan (The Omnivore's Dilemma)

"But, mate, my heart is sore for Christian diet. You mightn't happen to have a piece of cheese about you, now? No? Well, many's the long night I've dreamed of cheese--toasted, mostly--and woke up again, and here I were.""
— Robert Louis Stevenson

""Capella Flavor Drops are the perfect companion for flavoring coffee, tea even protein and diet shakes in as little as 3-5 drops. Flavor Drops come in a variety of flavors and sizes. Flavor Drops are also available to flavor water one bottle at a time. Flavor Drops is the only on-demand flavoring without any fats, calories, or sweeteners. Flavor Drops are perfect for diabetics since they contain no sweeteners of any kind." "
— Capella flavor drops

"Food is an important part of a balanced diet. "
— Fran Lebowitz

"[T]he salient question is whether the increasing awareness of [heart] disease beginning in the 1920s coincided with the budding of an epidemic or simply better technology for diagnosis."
— Gary Taubes (Good Calories, Bad Calories)

"1) Choose healthy high calorie foods such as: Nuts, nut butters, avocados, regular oil based salad dressings, vegetable oils, and olives. These foods all contain heart healthy mono and polyunsaturated fats.
- Try snacking on a handful of nuts or olives in between meals. Add nuts to salads, cereal, shakes, etc.
- Have peanut butter sandwiches; add peanut butter to shakes, oatmeal, or on fruit.
- Dip veggies into oil based salad dressings.
- cook with vegetable oils.
- Try avocado slices on sandwiches.
2) Eat frequently. Aim for about 3 meals + 3 snacks per day. If it's tough for you to eat this frequently try shakes (such as protein shakes, yogurt shakes, etc). For many people it's easier to drink their calories than to eat them.
3) Choose low fat dairy and lean meats most of the time. Dairy and meat products are a source of saturated fat, the type of fat associated with increasing the risk of heart disease. Although you're looking to gain, lean meats and low fat dairy products are still a better option (low fat NOT non-fat).
4) Choose meals and snacks that contain a mix of nutrients (carbohydrate, protein and fat) For example: a sandwich on whole wheat bread with turkey, low fat cheese, avocado slices and some lettuce and tomato.
5) When exercising, focus more on strength training which helps build muscle and mass than cardiovascular exercise which predominantly burns fat.
6) Choose regular beverages. Soft drinks are not the most nutritious option for weight gain, but they can contribute a lot of calories to your total daily intake. 100% juice is a better option than sodas or other soft drinks such as fruit punch or ice tea.
Good luck!
7) Don't smoke! Smoking speeds your metabolism and slows weight gain."
— Metabolism