“Diet” is a loaded word for many reasons; for some it conjures past or current hunger/fear from a poorly structured and unsustainable crash diet, for some, over sweetened foods and drinks with ingredients like “sucralose”, “aspartame”, and “stevia”. Although your diet can be used to reduce calories to achieve weight loss, as it is more commonly known, but can also be manipulated to other ends.
As many who have spent time in the strength training world can attest, “Cutting” and “bulking” often become a way of life to optimize muscle mass and strength gains while staying within a weight class or optimizing body fat for health or competition. This is done through two methods; burning more calories and/or reducing calories consumed.
Despite what many will tell you who wholeheartedly worship fad diets; there is no secret key to fat/mass loss (looking at you keto-ites) outside of creating a caloric deficit. When losing, it is important to continue training with intensity and consuming at least 0.8-2g protein/lb lean body mass to maintain as much strength and muscle mass as possible. On the other end; if you are not competing in strongman, gaining weight while limiting an increase in body mass (for those that are well trained, there will be some fat gained) is usually preferred. This often requires SLOW weight gain (¼ lbs-½ lbs/week), slowly increasing training volume/intensity, and adequate dietary protein intake. For those who call themselves “hard gainers” (myself included), this may require a not-so-clean bulk, adding up to 20% of calories in “junk” food. But I would still emphasize lean proteins, fruits and vegetables, and fiber-rich carbohydrate sources as the bulk of you diet.
For those trying to live their healthiest/best life, and as a basis for everyone's diet (what you eat) whether gaining/losing.maintaining weight, research has shown these principles likely to be the most important:
Consume mostly water as beverages
Eat A LOT of fruits and vegetables (5+ servings daily)
Eat mostly whole foods
Eat enough fiber (at least 35 grams per day from whole sources)
Eat enough protein (0.8 g/lbs minimum)
Minimize saturated fat intake (<10% of calories/day)
Eat a moderate amount of carbohydrates( 40-60% of daily calories)