Macronutrients are a type of food required in large amount in the diet. They’re your carbohydrates, fat, and protein. Macronutrients are essential for many biological processes. One of those processes is generating adenosine triphosphate (ATP) for energy.
In this article, we’re going to compare how four popular diets (intermittent fasting, ketogenic diet, Whole30 diet, and the paleo diet) utilize carbohydrates, fats, and protein as sources of fuel.
Intermittent fasting and the ketogenic diet
Intermittent fasting is a dietary strategy where you alternate between periods of fasting and regular eating. Although it should be said that most intermittent fasting dietary programs use modified fasting (you’re allowed small amounts of caloric intake) rather than real fasting (abstaining from all caloric intake).
Exactly how long you fast for and how often depends on the particular program you’re on.
There’s time-restricted feeding, alternate-day fasting, and Ramadan intermittent fasting.
- Time-restricted feeding means you only eat during specific hours of the day. The window typically ranges from 6-12 hours each day.
- Alternate-day fasting means you fast every other day.
- And Ramadan intermittent fasting means you fast during the daylight hours.
People generally like intermittent fasting because of its flexibility and because it is easier to maintain for the long term.
The ketogenic diet is a very low carb, high fat diet. The goal is to essentially replace all the calories you were getting from carbohydrates with calories from fat.
Like intermittent fasting, there are several different types.
- The standard ketogenic diet is very low carb, moderate protein, and high fat.
- The cyclical ketogenic diet is like the standard ketogenic diet, but with periods of high carb “refeeds”.
- The targeted ketogenic diet allows you to add carbs around workouts.
- And the high-protein ketogenic diet is the standard ketogenic diet, but with high amounts of protein instead of moderate amounts.
Let’s look at the way these two diets affect how your body generates energy. I grouped intermittent fasting and the ketogenic diet together because they both have a similar effect.
Your body relies on ATP to fuel the biological processes that make life as we know it possible. That’s just a rule. There’s no diet that can change the amount of ATP we use or don’t use.
What a diet can change is how ATP is generated.
Your body can create ATP from four different sources: creatine phosphate, carbohydrates, fats, and protein. And it will always do it in that order. If there is creatine phosphate around, your body will generate ATP from it. If there are carbohydrates around, your body will make ATP from that. Then it moves on to using fat as a source of ATP generation and, as a last resort, protein.
Carbohydrates can be found circulating in the blood and stored as glycogen in the muscles and liver.
When you’re fasting or you’re on the ketogenic diet, carbohydrates are limited. Since it’s the preferred method of generating ATP, your body will use up what’s available in the blood. Once that’s gone, glycogen stores will be converted to glucose and that will be used up.
Then, your body has no choice but to mobilize fat stores and use them to create ATP. The energy has to come from somewhere.
The Whole30 diet
The Whole30 diet was developed in 2009, riding the wave of the New York Times bestselling book, The Whole30.
The rules are relatively simple: for 30 days avoid real and artificial sugar, alcohol, grains, legumes, dairy, carrageenan, MSG, sulfites, baked goods, and treats (stay away from the sour dinosaurs!). Abstaining from all of these foods for a month supposedly eliminates cravings, restores a healthy metabolism, heals the digestive tract, and reduces systemic inflammation.
The diet isn’t so much about what you do eat, it’s about what you shouldn’t be eating.
What you can eat on the Whole30 diet are moderate portions of meat, seafood, and eggs. Lots of vegetables. Some fruit. And lots of herbs, spices, and seasonings. The general idea is that the less ingredients, and the more pronounceable those ingredients are, the better the foods are going to be for you.
The Whole30 diet shouldn’t really alter the macronutrients your body uses to generate ATP. Without the refined sugar and heavily processed carbohydrates, you’re going to avoid fast spikes and heavy drops of blood sugar levels. But, there still will be glucose circulating and enough carbohydrates coming in from your diet (the fruits and vegetables that you’re eating) to replenish glycogen stores in the liver and muscle.
The paleo diet
The paleo diet is designed to resemble what human hunter-gatherers ate eons ago – cause apparently they knew what was up when it comes to human nutrition.
The diet is based on eating whole foods and leading a physically active life.
The paleo diet is a lot like the Whole30 diet, there’s just fewer restrictions on the relative proportions of what you can eat.
First, things you have to avoid when you eat paleo:
- Sugar and high-fructose corn syrup
- Some vegetable oils (soybean oil, sunflower oil, cottonseed oil, corn oil, grapeseed oil, safflower oil)
- Trans fats (found in things like margarine)
- Artificial sweeteners
You can eat meat, fish, eggs, vegetables, fruits, nuts, seeds, herbs, spices, healthy fats, and oils. In any amounts you want to.
In terms of macronutrients you rely on, eating paleo puts you in the same boat as the Whole30 diet. It really depends on what eat (and their relative proportions) of the food your allowed to consume.
You can be paleo and have a high carb diet. You can be paleo and have a low carb diet. You could be paleo and be ketogenic or do intermittent fasting too. The macronutrients you use to generate ATP (whether it’s biased towards carbohydrates or fats) all depends on the amount of carbs in your diet and how often you’re eating those carbs.
There are lots of diets out there. Ultimately, which one works best for you depends on who you are, your lifestyle, and your goals.
Of the most popular diets, intermittent fasting and the ketogenic diet are the two that will most effectively burn fat as a source of energy. I prefer intermittent fasting because it is really adaptable and there is a lot of science backing up its health benefits.
Here’s a good article to check out if you’re interested: Intermittent fasting: Surprising update.