Why Do Keto, Intermittent Fasting, and Tracking Macros Actually Work?

So, you’ve probably heard of a friend who swears by the keto diet and how it helped them lose weight—claiming that all you need to do is eat a stick of butter before every meal, and your body will finally learn how to burn fat. Then there’s the friend who fasts for two days every three days, and somehow, it’s a “miracle” weight-loss method. They suggest just supplementing with meth and cigarettes to control hunger cravings. (Note: Please don’t actually do this!)

Another friend is all about the “If It Fits Your Macros” (IIFYM) life. They insist that tracking your macros and hitting specific protein, fat, and carb targets will make the fat melt off.

It’s easy to feel confused about which method is best. With so many diets out there claiming to be the magic solution, how is it that different approaches seem to work for different people? The answer? Insulin.

Let’s break this down simply.

The Role of Insulin in Fat Loss

To truly understand how your body loses fat, you need to grasp the role of insulin. It’s pretty simple: when insulin is present in the bloodstream, your body cannot access fat from its storage for energy. Insulin is the key regulator of fat metabolism, and in order to tap into your fat stores, you need to lower insulin levels.

Why does your body produce insulin? It’s designed to manage blood sugar levels. And why does your blood sugar rise? Because of carbohydrates.

The Food Pyramid and Its Connection to Chronic Disease

The food pyramid that became popular in 1974 and was widely adopted in the U.S. in 1992 recommended large amounts of grains, rice, cereals, and pasta. It’s no coincidence that around the same time, we saw a huge rise in heart disease, Type 2 diabetes, and obesity, with the largest spikes occurring from 1990 to 2000. This raises an important question: Could it be that the rise in carbohydrate consumption played a role in these health issues?

Now, back to the question: why do these diets work? The key is managing insulin levels.

How These Diets Impact Insulin and Fat Loss

1. Keto Diet The ketogenic diet focuses on drastically reducing carbohydrate intake (less than 30g of carbs a day) and replacing those calories with protein and fat. When you cut carbs, your blood sugar levels drop, and consequently, your body doesn’t need as much insulin to manage those levels. Lower insulin allows your body to burn fat for energy.
2. Intermittent Fasting In intermittent fasting (IF), a common approach is the 16/8 method—16 hours of fasting and an 8-hour eating window. During the fasting period, no food or calorie-dense drinks are consumed, meaning no carbohydrates are taken in. By not eating carbs, you naturally keep your blood-sugar levels in check, which results in better insulin management. This allows your body to start tapping into fat for energy instead of relying on carbs.
3. Tracking Macros (Flexible Dieting) Popularized by apps like MyFitnessPal, tracking macros is about balancing your intake of protein, carbs, and fats. Many people who start tracking their food intake end up reducing their carbohydrate consumption from 65-80% of their daily calories to about 20-30%. As a result, insulin levels decrease, allowing the body to burn fat more efficiently. This process is the same as the other diets: lower insulin, more fat-burning.

Calories and Fat Loss: It’s More Than Just Math

While calories still play a role in weight loss, it’s more complicated than just subtracting 500 calories a day to lose weight at a steady pace. If that were all it took, anyone would be able to drop a pound every week forever, until they weighed nothing. But that’s not how it works. The body is more complex than just thermodynamics.

The Big Takeaway: There’s No One-Size-Fits-All Solution

There isn’t a single solution for everyone when it comes to weight loss. The path you choose depends on your preferences, what you can sustain, and how your body responds. But no matter which approach you take, they all tend to emphasize reducing sugar and increasing vegetable intake—key elements for improving health and fitness.

Want to Dive Deeper into Nutrition?

If you’re looking for personalized guidance, we offer free Nutrition Consultation to help you understand your nutrition better and answer your questions. It’s a no-pressure opportunity to get the information you need to lose weight, gain muscle, and feel better.

P.S. You don’t have to start your weight-loss journey with exercise, but it sure makes it more fun!