Diets are a hotly debated topic and an ever-changing science. Even the word itself can mean a multitude of things to different people. At its root, “diet” refers to the kinds of food that a person habitually eats; in more modern society, it has also come to mean a short-term change in eating habits for a quick weight drop or body cleanse. However, the truth is that diets are different for everyone. No physical body is the same, and so it makes sense that no one diet has the same effects for every person. Weight loss may be the goal for some, and simply feeling better may be the goal for others. Choosing a diet is an individual experience, with individual goals and individual outcomes.
Because of this, it is extremely important for each person to have clear goals, set safe/healthy boundaries, and research heavily before making a decision to pursue a new diet, whether in the short term or long term. For someone looking to make a long term change to improve their daily health, longevity is a key decision factor; a diet that causes stress or feels too restrictive will not result in a long-term change, and is therefore ultimately an unsustainable choice. Consequently, choosing a regime to promote lifestyle changes that go along with personal values and preferences is important to maintaining a chosen diet.
The best way to start research on choosing the right one: comparing the required personal input and the general results of different diet types. It is also important to make sure the diets being considered are backed by scientific research and proven trial results. Take note of what the diet will require (cost, schedule, the amount of personal change in habit, etc), what risks are involved (if you have any pre-existing medical conditions, are pregnant, or have a history of disordered eating, many diets will not be safe for you), and what the expected results are (it is generally considered that losing 0.5 – 2.0 pounds per week is a safe range).
While there are a variety of diets to choose from, if weight loss is the goal, clinical trials like Duke’s Calerie show that sustained reduction of calories in some form is the best way to achieve that goal. To be clear, this means reducing calories below a person’s average daily intake, not starvation or deprivation of the body’s essential nutrients.
The following diets are some of the most commonly practiced for long-term use to implement weight loss and improved body composition in fitness training.
Kcal (kilocalorie) Diet
Kilocalories, the unit of energy that is commonly referred to as calories, are created in the body when food is ingested. If more calories are ingested than the body burns for energy, they are stored as fat. If less calories are ingested than the body needs for energy production, these stored calories are used as fuel to make up for the deficit of calories ingested. This balance between burning ingested calories and burning built-up stores of calories is what many diets base their reduced-calorie structure on.
Diets can restrict the type of calories ingested (carbs vs fats), the amount of calories ingested, or the periods of time when calories are ingested–and often offer a combination of these. The Kcal diet is a simple restriction of caloric intake in order to create a caloric deficit so the body burns stored fat. The generally accepted average of calories per day a person should ingest is 2500. With a Kcal diet, that daily caloric intake is reduced to 1500. These numbers can range up or down depending on how active or inactive a person considering this diet is, and while reducing daily caloric intake may be the simplest way to implement a diet, it could prove unsustainable for some to reduce calories indiscriminately. In that case, reducing specific types of calories may prove a better alternative for a sustained outcome.
Keto (Ketogenic) Diet
The keto diet focuses on altering the body’s energy process so that it burns fat for energy instead of carbohydrates (the molecules your body naturally burns for energy first), putting your body in a state of ketosis. To do this, participants of this diet severely limit carbohydrate intake and focus on eating foods with high fat and protein, like meats, eggs, cheese, oils, avocados, non-starchy vegetables, nuts, and seeds. It is a high-fat diet, but the fats and oils must be from non-processed foods to ensure the consumption of good fats (not fats or oils that are high in bad cholesterol).
Intermittent Fasting
Intermittent fasting cycles your body through periods of fasting (not eating) and eating. It does not restrict the foods eaten, but restricts when they are eaten. This method of reducing caloric intake pushes the body into temporary ketosis during fasting periods, when the body burns stored fat instead of recently consumed carbohydrates for energy.
There are many different patterns that can be used to implement intermittent fasting, and it is important to choose a pattern that will not be too taxing to stick to or result in overeating during the allotted meal periods. As an example, for people who travel often through different time zones, intermittent fasting can prove a difficult schedule to keep to and can become unsafe by overextending fasting periods. Fasting patterns work best for those that stick to a fairly regimented schedule each day.
Some of the common fasting patterns include the 16/8 method (16 hours of fasting, 8 hours of eating generally two meals and a few low calorie snacks), the 5:2 method (choosing two non-consecutive days to restrict caloric intake to 500-600 calories, not restricting the other five days), eat-stop-eat method (fasting for 24 hours on one or two non-consecutive days per week), and the warrior method (snacking on raw vegetables or fruits through the day, but only eating one big meal at night).
Choose what works for you
For those implementing a diet or increased training for the first time, it is best to work with professionals to ensure a safe transition into a new nutrition and fitness routine. Studies have concluded that clinically meaningful weight loss occurs from any reduced-caloric intake diet, so choosing a diet that is easier to stick to is one of the most important factors to consider. Being able to stick to a diet long term (in combination with a regular fitness routine and lifestyle choices that promote balanced mental fitness) is the key to losing a healthy amount of weight and maintaining the weight loss long-term.