These are all different types of diets that have drastically different rules and are sometimes completely opposing, yet ALL of them still work for different groups of people. Why do they all work?
Because the SPECIFICS of the diet does not matter. All of these diets can be successful through a combination of the following factors:
- Reduced calorie intake (mainly)
- Increased protein intake
Let us take a look at each of them individually.
High carb, low fat: Almost completely removes a macronutrient from the diet that may result in fewer calories being consumed.
High fat, low carb: See above.
Keto: Completely removes carbohydrates from the diet, which can result in fewer calories being consumed.
Carnivore: Removes carbohydrate intake and severely limits your food options, possibly resulting in an increase in protein intake and reduction in calories.
Vegan: Removes animal products from the diet, forces you to eat a higher fibre, higher carbohydrate diet. It also restricts your ability to eat many processed foods as most will contain animal products, all of which could cause a reduction in calorie intake.
Paleo: Removes all processed foods. This forces you to eat whole foods which are naturally lower in calories (per volume) and usually provide a higher protein and fibre content.
Pescetarian: A pescetarian diet is largely plant-based with the exception of fish. Plant-based diets are typically low in calories, due to their high fibre and low-fat content.
Vegetarian: Again, largely plant-based with the exception of eggs and dairy products.
IIFYM: If It Fits Your macros can work by forcing you to hit a macronutrient and calorie goal. Whilst there is more freedom with what you can eat, you must keep track of your exact macronutrient and energy intake.
As you can see there is nothing inherently special about ANY of the diets mentioned above. They simply make it harder to OVER-CONSUME calories by either focusing on the consumption of whole-foods, removing food groups or literally counting calories. No matter what kind of glorifying comments someone makes about why their particular diet is the be-all and end-all, it always comes back to this. Is there more to a diet than controlling calories? Of course, there is. Though there is no other single factor that has nearly the same impact on overall health. Consuming a healthy amount of calories, that keeps you within a healthy weight range is the number one, stand-alone option that we have for improving health through nutrition.
The next best nutritional intervention out there, that a lot of these diet options fail to address, is an increased protein intake. Protein is good for a lot of things! Though the main benefit is the maintenance and/or increase in muscle mass. Increasing muscle mass is important for energy expenditure, insulin sensitivity and joint health amongst a host of other benefits. If your diet is based around animal products then you probably won’t have too much of an issue with getting enough protein. On the flip side, a diet that removes animal products will typically fail to provide enough protein unless there is supplementation or a planned protein strategy. It is vitally important that those who follow a vegan diet are aware of their amino acid needs and either pair foods or supplement with a complete protein source to ensure they are getting the recommended amount of each amino acid. Pescetarians and vegetarians are at less risk of deficiency, as long as they do include either fish or eggs/dairy on a daily basis.