"Meal prepping sucks" is a term that gets thrown around from time to time. The truth of the matter is we've grown accustomed to others preparing food for us, with the likelihood of poor choices made during the process.
Yes, it's true. Nutrition and the timing of cosumption is crucial pertaining to your goals, easily 70-80% of the time.
Starting each day with a plan is important, and without one it can lower one's chances of obtaining their goals. Breakfast has long been told to be the most important sitting, due to the body's need of using those nutritents almost immediately after the last bite. Lean proteins, with complex carbohydrates & good fats is ideal.
Making smarter choices when eating out is important for many reasons. The most obvious, is making sure the right amounts of nutrients is included for maximum absorption. Make sure prior to walking or sitting down at a restaurant, research your preferred dish & read the nutrient facts and ingredients and make sure it's ideal with what your body needs.
It's also ok to eliminate certain ingredients (ex. butter, oils, cheeses, etc) to limit the amount of saturated fats you're likely to consume depending on the dish. Make sure protein, complex carbs & unsaturated fats are included. Refrain from simple/refined sugars, and high portioned items. Sodium may sometimes be a contributing factor, so as stated it's ideal to read the nutrient facts before entering the restaurant to have a better knowledge of what you're putting in your mouth.