I’m Low Carb. Shouldn’t I ALSO Eat Low Fat to Burn Body Fat?

I’m Low Carb. Shouldn’t I ALSO Eat Low Fat to Burn Body Fat?

Video | Getting Fat Adapted | Low-Carb/Low-Fat | Low-Carb/Reduced-Fat | The Protein Debate | Example | When to Change Your Diet | Burning Fat or Carbs [Devices] | Takeaway

I love my low carb diet. But, if I have too much body fat, do I really need to eat fat? Wouldn’t it make more sense to also keep my fat intake low and let my body burn the fat that’s already stored? This is a common question that you may have about a keto or low-carb/high-fat diet. We’ll discuss the answer in this blog post. 

Lowering Fat Once Fat Adapted – At-A-Glance


  • Fat adaptation occurs when you have restricted carbs enough to induce an increase in fat burning.
  • Following a low carb/high-fat diet helps your body become fat adapted. However, this adaptation takes at least a month.
  • Lowering your fat intake before reaching fat adaptation will not improve fat loss.
  • Reducing your fat intake after reaching fat adaptation may improve fat loss. 
  • How much you will need to reduce your fat intake will depend on many variables. Start with a 10% reduction and observe the changes. 

I’m Low Carb. Shouldn’t I ALSO Eat Low Fat to Burn Body Fat? [Video]

In this video, you’ll learn…

  • How to get fat-adapted.
  • Why a low-carb AND low-fat diet doesn’t work.
  • How a low-carb and reduced-fat diet could work for you.

Train Your Cells to Run on Fat 

I understand the thought process. If I am carrying around extra fat, why don’t I just eat low-carb and let my body supply the fat it needs for energy? This can happen – eventually. However, a vital first step is getting your body adapted to running on fat as its primary fuel. Your cells must be trained to do this, which is a state that you may have heard me refer to as being fat-adapted.

Getting Fat-Adapted (Carb-Burner vs. Fat-Burner)

Carbohydrates are an easy energy source for your body. It is a much easier source than pulling fat out of storage. However, carbs burn up quickly. If you have been eating a diet high in carbohydrates, your body is “carb-adapted” and looks for them as its primary energy source. Therefore, if you reduce your carb intake, your body will ask you to feed it more by turning on cravings.

Dietary fat – that you eat – is more accessible than stored fat. With fewer carbs to burn, the dietary fats help your body develop the enzymes and pathways needed to become a better fat-burner of both dietary and body fat. In plain words, following a low carb/high fat diet trains your cells to run on fat, and with time, you become fat-adapted. 

Getting Fat-Adapted

That explains why you need to feed your body fat as you transition away from a high-carb diet. The question then becomes, once your body is fat-adapted, why not stop eating fat and let your body burn the fat it already has stored?

Low-Fat vs. Reduced Fat

There are two separate ideas here. The first is the idea of eating a low-carb AND low-fat diet, where fat makes up less than 30% of your diet (1).

The second is the idea of reducing your fat intake, where you are bringing it from a high percentage of your daily calories to a moderate level. For example, going from 70% down to 50% or 60%.

Low Carb and Low Fat =No 

Let’s consider the first choice: a low-carb AND low-fat diet. This will not get you the result you want. Even after your body is fat-adapted, it will need energy from your diet, which you will supply by consuming fat. 

Three main nutrients supply your body with calories. They are carbohydrates, fat, and protein. Of those three, only carbs and fat are readily used as energy. Protein is not a primary choice because it is a basic building block for many structures inside you. Using it as a primary fuel would be like burning down your house to stay warm. 

Low Carb and Low Fat =No 

You are left with just two main sources of caloric energy: carbs and fat. If your diet is low in both, fat loss barriers come into play. For one thing, with carbs and fats out of the picture, you need to eat a lot more protein.

A very high-protein diet will raise insulin levels, working against the release of fat from your fat cells. Also, your body doesn’t want to waste protein by burning it for energy, so your body is wondering why you are starving yourself and goes into the defensive position of starvation mode. 

Low Carb and Reduced Fat =Plausible

The low-carb and low-fat diet approach is problematic. But, what about the second choice, involving the reduction of dietary fat? So, instead of fat making up 70% of your daily calories, it makes up just 60%, for instance. 

There are a handful of studies involving fat-adapted individuals. However, I have not seen a study supporting this rather specific idea that these individuals improve their results when they reduce their fat intake. However, in my opinion, there is some logic to this approach.

The things that we must consider are, how high can you go with protein? How low should you go with fat? And when is the right time to make this macronutrient switch? 

Low Carb and Reduced Fat =Plausible

The Protein Debate

How much protein your body needs is a highly debated topic with strong opinions on every side of the debate. And to further muddy the waters, your protein needs change when certain factors are present. You can’t point to two 150-pound individuals and say they both need 54 grams of protein per day.

Each person’s actual amount depends on many factors, including their activity level, age, muscle mass, and overall health. What we do see is that many research studies consider a high-protein diet to be one in which your daily calorie intake exceeds 30% (2)(3).

For this blog post, we’ll use 30% as our high for protein intake.

What Does Reduced Fat Mean?

As for how low to drop your fat intake, it will depend on your body. To do this properly, you need to know how much of your caloric intake currently comes from fat. To make things easy for this post, we’ll run through an example using a 10% drop in fat intake. 

What Does Reduced Fat Mean?

Example of a Low Carb/Reduced Fat Diet

Let’s say you typically eat a keto diet, consuming 1,500 calories daily with a 70-20-10 macronutrient breakdown. In other words, 70% of your daily calories come from fat, 20% from protein, and 10% from carbs. 

Now, you want to reduce your fat intake by 10% to encourage the burning of more body fat. So you shift your diet to a 60-30-10 macronutrient breakdown. In other words, you drop your fat intake by 10%, increase your protein intake by 10%, and keep carbs at their original low.

What does that look like in terms of actual food? 

You might be surprised to see how little of a food swap is needed to pull off this 10% shift. 

You can simply cut out two tablespoons of butter and replace them with 4 ounces of chicken [The calculation is based on a 1,500-calorie diet with a 70-20-10 (fat, protein, carb) macronutrient breakdown]. 

Before I go any further, I am not telling you to stop eating butter and start eating chicken. That is not my message. I chose these two foods because one is mostly fat, and the other is mostly protein.

I wanted to share an example to demonstrate how easy it can be to go overboard with change. You don’t want to get into the mindset that dietary fat is bad and end up eating a low-carb and low-fat diet. 

When Do You Make the Diet Switch?

Now that you have an idea of what a reduced fat diet looks like, the last thing to consider is when to make the switch. This is really a question of knowing when you’ve reached fat adaptation. I have a blog post that details building a fat-adapted metabolism

I can tell you that it takes at least a month of consistent adherence to your low carb/high fat diet. So, you cannot try to fool your body by reducing your fat intake too soon. If you do, your body will go right back to carb cravings.

How Do You Know Your Body is Burning Fat? 

Some devices can help you determine what your body is burning, fat or carbs. For instance, if you are following a keto diet, a ketone meter (e.g., Precision Xtra or Keto Mojo) tests your blood for the presence of ketones. Ketones are normal compounds that show up in your body when glucose is running low. Ketones come from the breakdown of fat, so if they are present, fat is being burned.

Breath analyzers (e.g., Lumen) test your breath to let you see if you are burning carbs or fat, making them beneficial for both keto and low carb dieters. However, remember that these devices tell you what is happening in the moment. Fat adaptation is a changed metabolic state within your body. You can use these devices to ensure you are on the right track, but to reach the fat adapted state, you’d want to see consistent results for at least a month. 

Blood Meter and Breathalyzer

Takeaway

Keto and low carb diets have been a godsend for many people. However, since I have been teaching this eating style, the diets have been diluted by a flood of keto-friendly snacks and products. These junk food knockoffs are the most significant barrier to continued success on a low carb or keto diet. 

If you have found that your weight loss has stalled, the first step is to cut out keto snacks. Step two is to track your current macronutrient intake to know how much fat you currently eat. Step three is to give this reduced fat concept a try. 

Thank you for reading and have a wonderful week!

References: 

(1) Bhandari, Priyanka, and Amit Sapra. “Low Fat Diet.” (2020).

(2) Veldhorst, Margriet AB, Margriet S. Westerterp-Plantenga, and Klaas R. Westerterp. “Gluconeogenesis and energy expenditure after a high-protein, carbohydrate-free diet.” The American journal of clinical nutrition 90.3 (2009): 519-526.

(3) Veldhorst, Margriet AB, et al. “Presence or absence of carbohydrates and the proportion of fat in a high-protein diet affect appetite suppression but not energy expenditure in normal-weight human subjects fed in energy balance.” British journal of nutrition 104.9 (2010): 1395-1405.

About the Author

Becky Gillaspy, DC, is the author of The Intermittent Fasting Guide and Cookbook. She graduated Summa Cum Laude with research honors from Palmer College of Chiropractic in 1991. 

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