I'm not sure if there's really some truth to the whole "not eating anything after 6pm" rule. If you eat something small and healthy, like... an apple, what's the harm? Just redistribute what you eat through the rest of the day so you're not consuming excess calories. Weight loss occurs when you burn more than you take in.

Just adding on to what 212 said: While every weight loss plan might not work for everyone, the bottom line is calories in vs. calories out, i.e. eat less, move more. When you consume/use your calories does not matter as long as you create a deficit each week. Also, WHAT you consume doesn't really matter either -- you could eat nothing but Twinkies and still lose weight. (Google it; someone actually did this.) The reason people say to eat healthier foods when losing weight is because when you lower the amount of food you eat, you are also lowering the amount of nutrition you get, so yeah, generally, it's smarter to eat low cal, nutrition-packed foods so you don't feel like shit all the time while you lose weight. However, healthy food is not necessary for weight loss to occur. If you maintain on 2000 calories worth of food from McD's every day, then you'll still lose weight on 1500 calories worth of McD's. You'd also lose on 1500 calories worth of lean meats, non/low fat dairy, whole grains, fruits, and veggies. That being said, like I said before, not every plan works for everyone. While I lose weight simply by calorie counting (i.e. eating whatever I want within a certain calorie limit), you might would need to count your carbs in addition to calories, and #212 might would do better on a points exchange system. Preaching at someone on how they should go about weight loss is silly because while yes, all of those "rules" are generally good rules for weight loss, but they might not work for everyone. This quote best describes the best formula for successful weight loss: "The “perfect” diet is the foods you’ll eat and the “perfect” workout is the one you’ll do."