Should You Eat Low-Carb or High-Carb for Fat Loss?

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Calories count and macronutrients matter, but that doesn’t mean the same macronutrient amounts will work for everyone.

If you want to lose fat, you should be eating a fairly high protein diet. However, how much carbohydrate and fat you eat is more variable.

There are pros and cons to both high- and low-carb diets, and neither is best in ever situation. In this podcast, you’re going to learn how to decide which kind of diet is best for your goals.

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All The Rest” by Talley Lambert

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### References

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### Transcript

**Armi Legge:** There is a war going on right now in the fitness industry. One side says that carbohydrates make you fat and/or hungry and you need to avoid them in order to lose fat. The other side says that fat makes you fat and that high-carb diets are better for fat loss.

Actually, that’s what’s called a “false dichotomy” because there’s also a third side that doesn’t believe either of those things. The third side understands that calories count and macronutrients matter but also that different people are going to prefer or require different diets to reach their goals.

In this podcast, we’re going to compare and contrast the high and low-carb diets and see which one is more suited to certain situations.

My name is Armi Legge and you are listening to Impruvism Radio, the podcast that gives you simple, science-based tips to improve your health, fitness, and productivity.

If you like what you hear on today’s show, go to impruvism.com. Enter your email address in the box on the right side of the page and click the button below. After you do, you’ll get free updates from the Impruvism blog when they are published.

I’m going to preface this by saying that it’s actually hard to define what constitutes low or high-carb. Most people use diet percentages. They often say that high fat diets have more than 30% of calories from fat or that high-carb diets have more than 50% of calories from carbs, or some other arbitrary cut-off.

The fact is that diet percentages aren’t very useful in most cases. Your macronutrient needs are largely based on your body size and activity level, so dividing your calories according to percentages don’t really help you that much.

In most cases, people like high level athletes may need to eat 75% or 80% of their total calories from carbohydrates, yet they’re also still eating a high-fat diet. For instance, Tour de France cyclists often eat over 1,000g of carbs per day but they’re also eating more than 100g of fat, which is about 1,000 calories worth. Interestingly, they also often eat between 250g and 300g of protein per day. So if someone is eating around 2,000 calories per day ate the same amount of fat as a pro cyclist eating 7,000 or 8,000 calories per day, that would be over 50% of their total calories, which would be considered a high fat diet even though it would be the same amount of fat as somebody who is also eating many hundreds of grams of carbohydrates.

Basically, some people have such high energy needs that they need to eat a high-everything diet. It makes percentages less useful.

However, in this podcast, we will generally define diets by their carbohydrate content. If a diet has more than about 100g of carbs, we’re going to call it a high-carb diet and if it has less than that, we’ll call it a low-carb diet. Obviously, there is a ton of gray area in there as well.

Now let’s talk about whether high or low carb diets are better for certain people’s goals.

Before you worry about your carbohydrate or fat intake, you need to make sure you’re eating enough protein. If you’re trying to lose fat and/or are very active, your protein intake should be fairly high, about 2.2g of protein 1kg of body weight. You should also be eating lots of fruits or vegetables no matter what kind of diet you’re on. Assuming you’re eating enough protein and produce, let’s talk about five types of people who might benefit from a lower carb diet.

1) People who prefer fat over carbohydrates.

First and foremost, you need to consider your personal preferences. If you like fat more than carbs, then it’s fine to eat more fat. If you’ve been reading the articles on impruvism.com about flexible dieting, you know that you should set up your diet based on personal preference first.

Some studies have found that dieters rate low-carb diets as more palatable and easier to follow than high-carb diets. This is probably because most people have been actively restricting their fat intake per the recommendations they see everywhere. So being allowed to eat more is a great treat.

Many people also like the structure of low-carb diets, which improves adherence, and they like not having to count calories at least at first. If people can stick to their low-carb diet in the long-term and not overeat if they get bored with their diet, low-carb by itself can work perfectly well.

2) People who are less insulin sensitive.

People’s baseline insulin sensitivity can vary about 10 fold, meaning one person might be far more carbohydrate tolerant than another. At least one study has found that, under free living conditions where people were allowed to eat meals the researchers had prepared at home, the people who were less insulin sensitive lost more fat on a low-carb diet. This is probably because they felt better eating low-carb and thus stuck to their diet better.

There haven’t been many other studies like this one, but it still indicate that some people may be physiologically better matched with low-carb diets than high-carb ones and that this can have an impact on their long term adherence.

However, keep in mind that both exercise and calorie restriction increase insulin sensitivity. If you’re exercising regularly and you are in a caloric deficit, you might be just fine on a higher carb diet even if you aren’t insulin sensitive to begin with.

3) People who are overweight.

Generally, overweight people are more sedentary and less insulin sensitive which means low-carb might work better for them. If you’re setting up a diet for an overweight or obese person, it’s generally a good idea to err on the side of lower rather than higher carb, at least in my opinion. There is also good evidence showing that, among overweight people, low-carb diets can often do a better job of improving cardiometabolic health like glucose and triglyceride levels.

4) People who are sedentary.

People who don’t exercise or move very much generally have much lower total energy needs and are burning very little carbohydrate. Many sedentary people can still do just fine on a higher carb diet since their bodies will burn more carbs, but they don’t need them like somebody who is training hard.

A lot of people say that you need to “earn your carbs” through activity and that is sort of true. However, if you’re mostly sedentary, you can still “earn your carbs” by eating less fat and keeping your calories under control and you’ll still do just fine.

5) People who often overeat carbohydrate-rich foods.

Perhaps one of the best reasons to go low-carb is if you have trouble eating carbs in moderation. When many people think of carbs, they think of candy, energy bars, pasta, and sugary cereal– all of which are very calorie dense and not very filling. These foods are easy to overeat. When people eliminate these carbs, they eliminate a lot of trigger foods that they have trouble consuming in moderation.

You could also get plenty of carbs from starchy vegetables, oats, potatoes, and other whole foods that also keep you full, but for some people, it’s easier to eliminate or just limit all carbs.

Most people spontaneously eat less when they eliminate all carbs. They cut out an entire food group and, if they’re like most people, they were eating a lot of not very filling, sugary foods to begin with. When they stop eating these foods, they can’t help but eat fewer total calories and lose fat.

There’s also some evidence that ketogenic diets, ones that keep carbs below about 50g – 100g per day, might help blunt hunger, but the effect isn’t very consistent and there isn’t enough data to show this is meaningful over the long-term.

Now let’s discuss the people who might be better under a higher carbohydrate diet.

1) People who prefer carbohydrates over fat.

Once again, start with personal preference. If you like carbs more than fat, then eat more carbs.

Most people also spontaneously eat less when they eliminate fat just like they do when they eliminate carbs. While low-carb gets the most credit in this regard, low-fat diets also often help people eat less without counting calories.

When you reduce your fat intake and keep eating roughly the same amount of everything else, you often eat less without realizing it.

However, people can get bored with high-carb diets, too, which is why this is often not a very effective long-term strategy.

2) People who are training a lot, especially those doing a lot of high-intensity training.

In general, the higher your energy needs, the more carbohydrates you should eat. This is because, in most cases, people with extremely high energy needs are burning those calories through lots of exercise.

Studies have consistently shown than higher carb diets do a better job of supporting heavy training. In fact, they’re also essential for high intensity training. This includes pretty much anything over about 80% of your maximum heart rate, including virtually all forms of weight training. Technically, you can perform lots of lower-intensity training on a low-carb diet, but even then, studies have usually found that people don’t perform as well. They can’t cover the same distances as fast. They fatigue faster. They receiver slower. And they generally don’t gain as much strength.

There’s also a silly idea about there about fat adaptation including endurance performance, but we can cover that in a different podcast. For now, I’ll just say that it’s inaccurate.

High-carb diets also tend to do a better job of limiting cortisol levels during heavy training. Other studies have found that people tend to gain more strength on high-carb diets than even moderately high-carb diets, probably because they can train harder, perform better in their workouts, and receiver faster.

High-carb diets also tend to do a better job of maintaining thyroid and leptin hormone levels, which is important while dieting. Controlled studies haven’t found any difference in weight loss between high and low-carb diets, but keeping thyroid and leptin levels higher might still help people feel better and recover faster while dieting.

This is more of an issue for people dieting to the extreme limits of leanness like bodybuilders, athletes, and models rather than your average person trying to lose a few pounds.

3) People who are more insulin sensitive.

As you just learned, some people are more insulin sensitive than others and are probably going to do better eating a high-carb diet. This might also change based on their preferences and training.

4) People who have trouble eating fat in moderation.

As you almost certainly heard before, fat has about twice as many calories as carbohydrates, so technically it can be easier to overeat.

It’s also true that high-fat food encourage passive overconsumption. Basically, people eat a lot more calories without realizing it because the food doesn’t have much total volume.

For instance, peanut butter has about 100 calories per tablespoon, which is about the same as butter. This doesn’t mean that you should never eat peanut butter but for many people it’s easy to overdo because a tablespoon just isn’t that much. On the other hand, many carbohydrate rich foods are also very high in fiber, water, total food volume, and fairly low in calories comparatively.

People tend to eat about the same amount of food volume per day, so replacing some of that volume with starchy, voluminous foods like potatoes and bananas can often help people eat less. Fat tends to take up less space, which is why it’s easy for some people to overeat it.

In most cases, there is a ton of flexibility in how much carbohydrate and fat you need per day. After you set your total calorie and protein intake, how much fat or carbohydrate you eat is largely optional. In most cases, it really doesn’t matter that much. This is assuming that you’re moderately active, getting to the gym 2 or 3 times per week and doing some cardio or light movement on the other days, and you’re not taking your diet to wild extremes in either direction (e.g., eliminating all carbs or all fat).

There’s also no reason you need to choose between high and low-carb. It’s also fine to change your diet over time, or even on a daily basis. If you want to prepare a meal that is higher in fat one day, then eat less carbohydrate. If you have hardly any fat one day because you wanted more carbs, that’s fine, too.

You aren’t going to hurt yourself if you don’t eat as much carbs or fat one day as you did previously. What matters are averages over time. For athletes, eliminating carbs is generally more noticeable and immediately detrimental, but even then there’s some leeway on how much you have to eat per day. Frankly, I’m a little surprised people aren’t recommending this approach more.

For instance, you might have someone eat low-carb for a few weeks and then high-carb for a few weeks. Granted, this kind of behavior change won’t work for everyone, but it’s worth trying if you’re absolutely determined now to count calories. Even if you are counting calories, it’s a nice way to keep your diet interesting.

Of course, you can also do this on a day-to-day basis as well. In most cases, a moderate carb, moderate fat diet tends to work best.

As we talked about at the beginning of this podcast, diet percentages aren’t very useful, but something around 30% – 40% of your diet from protein and the rest split evenly between carbs and fat is a good baseline for most people with fairly average energy needs. That gives you enough variety to keep your diet interesting. It allows you lots of food choices. And it gives you the benefits of both high and low-carb diets.

You have enough carbohydrate to support your training and feel good and keep your hormones higher, and you have enough fat to keep you full, happy, and healthy.

This kind of moderate-carb and moderate-fat diet is also a great starting place to experiment from. If you find you’re not performing very well in your workouts, you might want to eat more carbohydrates. If you feel like it’s harder for you to control your calorie intake while eating so many carbs, then eat less.

Before we finish up, let’s talk about how to decide which diet might be right for you.

In a recent article on Flexible Dieting on impruvism.com, I listed that you should design your diet with personal preference in mind first and then modify that diet based on your goals, and then take into account any medical or physiological reasons why you might need to limit certain foods. Let’s use that same approach here.

Set protein intake first. Eat plenty of fruits and vegetables. After that, here are the questions you should ask yourself:

Do you prefer carbs or fat?
Eat more of whatever you would like more.

Are you exercising a lot?
Especially at at a high intensity? If so, eat more carbs. If not, eat less.

Are you trying to gain muscle or compete in an endurance sport?
If so, eat more carbs.

Are you trying to lose fat?
If you have trouble eating carbs in moderation, try low-carb. If you have trouble eating fat in moderation, eat less fat.

If you’re also exercising a lot while trying to lose fat, then eat more carbs.

If you’re already very lean to begin with and you’re dieting, then eat more carbs

If you’re not very active but you’re in a caloric deficit, then go with whatever you like more. Or switch things up on a daily or weekly basis.

Do you like both carbs and fat?
Then eat more carbs on some days and more fat on other days, keeping your calories in check.

Are you tired of eating low or high-carb?
If so, then eat more of the other macronutrient.

Are you more or less insulin sensitive?
If you’re less insulin sensitive, start out with a lower-carb diet. If you’re more insulin sensitive, then do the opposite.

Are you a moderately active person who likes both carbs and fat and is trying to either maintain their weight or lose a little weight?
Then eat a moderate to high protein, moderate-carb, moderate-fat diet, control your calorie intake, and change your diet over time based on your personal preferences.

In most cases, it really doesn’t matter that much as long as you’re eating enough protein and keeping your calories at the appropriate level for your goals.

So here’s the 8-point summary of whether high or low-carb diets might be better for certain people.

1) Eat enough protein and produce within your calorie goals no matter what amount of fat or carbohydrate you eat.

2) If you like more carbohydrate or fat, then eat more of that macronutrient.

3) If you’re doing a lot of endurance and/or strength training, trying to gain muscle, and/or are dieting to very low body fat levels, then eat more carbohydrates.

4) If you are less insulin sensitive, then you may benefit from eating less carbohydrate.

5) If you have trouble eating carbs or fat in moderation, then eat less of that macronutrient.

6) Don’t go to extremes in either direction. Eat at least some fat and carbohydrate. Generally no less than 10% – 15% of your total calories from fat and no less than 50g of carbs is a good range.

7) Adjust your diet based on real world results and personal preference. Don’t be afraid to change it.

8) In most cases, it really doesn’t matter after you’ve set your protein and calorie goals. Be flexible about your diet. It works better.

You can find links to everything we talked about in today’s show on the show notes for this episode on impruvism.com.

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