GasparJohnson

As @Rudynate said, opinion is varied. Personally, I do not think that it is necessarily bad...but it is not better than post-prandial (fed) cardio:
 
The theory makes sense: if your body doesn't have fuel in the form of recently-consumed food, you will tap into your body's fat stores for fuel. However, the scientific literature indicates that:
 
1. There seems to be some sort of "metabolic adaptation" if you eat and then exercise, your metabolism staying elevated after exercise if you eat before doing cardio.
2. Doing cardio on an empty stomach is likely to increase cortisol levels, a hormone which can make fat loss difficult if levels are too high.
3. Eating before exercising will give you more energy, thus enabling you to burn more calories. They may not all be from fat since you are in a fed state, but trying to target a certain fuel source is very difficult given the complexity of human physiology.
 
Furthermore, a 2014 study published in the Journal of the International Society of Sports Nutrition divided women into two groups: empty stomach cardio and fed cardio. At the end of the study, women in both groups had lost weight, but there was no difference between the two groups.
Link: https://jissn.biomedcentral.com/articles/10.1186/s12970-014-0054-7
 
 
Once again, I'm not saying that cardio on an empty stomach is "bad." A LOT of people have lost weight by doing it--it was especially popular during the "Golden Era" of bodybuilding. However, the research seems to show that it doesn't really matter when you do it--and that trying to theorize how hormone levels at different times of the day are going to affect fat oxidation is extremely difficult given the amazing complexity of the human body.
 
As long as you do your cardio consistently and eat to be in a caloric deficit, it doesn't really matter.

As @Rudynate said, opinion is varied. Personally, I do not think that it is necessarily bad...but it is not better than post-prandial (fed) cardio:
 
The theory makes sense: if your body doesn't have fuel in the form of recently-consumed food, you will tap into your body's fat stores for fuel. However, the scientific literature indicates that:
 
1. There seems to be some sort of "metabolic adaptation" if you eat and then exercise, your metabolism staying elevated after exercise if you eat before doing cardio.
2. Doing cardio on an empty stomach is likely to increase cortisol levels, a hormone which can make fat loss difficult if levels are too high.
3. Eating before exercising will give you more energy, thus enabling you to burn more calories. They may not all be from fat since you are in a fed state, but trying to target a certain fuel source is very difficult given the complexity of human physiology.
 
Furthermore, a 2014 study published in the Journal of the International Society of Sports Nutrition divided women into two groups: empty stomach cardio and fed cardio. At the end of the study, women in both groups had lost weight, but there was no difference between the two groups.
Link: https://jissn.biomedcentral.com/articles/10.1186/s12970-014-0054-7
 
 
Once again, I'm not saying that cardio on an empty stomach is "bad." A LOT of people have lost weight by doing it--it was especially popular during the "Golden Era" of bodybuilding. However, the research seems to show that it doesn't really matter when you do it--and that trying to theorize how hormone levels at different times of the day are going to affect fat oxidation is extremely difficult given the amazing complexity of the human body.
 
As long as you do your cardio consistently and eat to be in a caloric deficit, it doesn't really matter.

As @Rudynate said, opinion is varied. Personally, I do not think that it is necessarily bad...but it is not better than post-prandial (fed) cardio:
 
The theory makes sense: if your body doesn't have fuel in the form of recently-consumed food, you will tap into your body's fat stores for fuel. However, the scientific literature indicates that:
 
1. There seems to be some sort of "metabolic adaptation" if you eat and then exercise, your metabolism staying elevated after exercise if you eat before doing cardio.
2. Doing cardio on an empty stomach is likely to increase cortisol levels, a hormone which can make fat loss difficult if levels are too high.
3. Eating before exercising will give you more energy, thus enabling you to burn more calories. They may not all be from fat since you are in a fed state, but trying to target a certain fuel source is very difficult given the complexity of human physiology.
 
Furthermore, a 2014 study published in the Journal of the International Society of Sports Nutrition divided women into two groups: empty stomach cardio and fed cardio. At the end of the study, women in both groups had lost weight, but there was no difference between the two groups.
Link: https://jissn.biomedcentral.com/articles/10.1186/s12970-014-0054-7
 
 
Once again, I'm not saying that cardio on an empty stomach is "bad." A LOT of people have lost weight by doing it--it was especially popular during the "Golden Era" of bodybuilding. However, the research seems to show that it doesn't really matter when you do it--and that trying to theorize how hormone levels at different times of the day are going to affect fat oxidation is extremely difficult given the amazing complexity of the human body.
 
As long as you do your cardio consistently and eat to be in a caloric deficit, it doesn't really matter.

As @Rudynate said, opinion is varied. Personally, I do not think that it is necessarily bad...but it is not better than post-prandial (fed) cardio:
 
The theory makes sense: if your body doesn't have fuel in the form of recently-consumed food, you will tap into your body's fat stores for fuel. However, the scientific literature indicates that:
 
1. There seems to be some sort of "metabolic adaptation" if you eat and then exercise, your metabolism staying elevated after exercise if you eat before doing cardio.
2. Doing cardio on an empty stomach is likely to increase cortisol levels, a hormone which can make fat loss difficult if levels are too high.
3. Eating before exercising will give you more energy, thus enabling you to burn more calories. They may not all be from fat since you are in a fed state, but trying to target a certain fuel source is very difficult given the complexity of human physiology.
 
Furthermore, a 2014 study published in the Journal of the International Society of Sports Nutrition divided women into two groups: empty stomach cardio and fed cardio. At the end of the study, women in both groups had lost weight, but there was no difference between the two groups.
Link: https://jissn.biomedcentral.com/articles/10.1186/s12970-014-0054-7
 
 
Once again, I'm not saying that cardio on an empty stomach is "bad." A LOT of people have lost weight by doing it--it was especially popular during the "Golden Era" of bodybuilding. However, the research seems to show that it doesn't really matter when you do it--and that trying to theorize how hormone levels at different times of the day are going to affect fat oxidation is extremely difficult given the amazing complexity of the human body.
 
As long as you do your cardio consistently and eat to be in a caloric deficit, it doesn't really matter.

A lot of good comments here. I'll add mine:
 
I think that what @Eric Hassan said is very important: counting not only calories but also macronutrient ratios (protein, carbs, and fat) is very important for two reasons:
 
1. Not all foods have the same number of calories. There are some foods of which you can eat a lot and not eat that many calories; however, other foods, even "healthy" foods, can be very high in calories. For example, if you Google the nutrition information for 100 gram servings of foods, you will see that per 100 grams:
 
Tomato: 18 calories
Apple: 52 calories
Banana: 89 calories
 
 
As you can see, for the same amount of food (as weighed in grams), you can eat a lot more tomato and apple than banana. That doesn't mean that you shouldn't eat bananas if you want to lose weight: you definitely can (they are a good source of potassium, inexpensive, always in-season, etc.), you just have to be aware that they are more calorific than almost all other fruits and vegetables.
 
2. Even though a lot of people have had success with low-carb diets, the scientific research actually suggests that your body more easily stores a fat surplus than a carbohydrate surplus. In fact, there is a study published in the American Journal of Clinical Nutrition showing that in a 14-day study in which people were purposefully overfed calories, one group overfed with carbohydrates and the other overfed with fat, the group overfed with fat gained MORE bodyfat than the carbohydrate group. The difference was especially pronounced in the beginning of the study since humans have to fill up their muscle glyocgen stores in order to convert a significant amount of carbohydrates to body fat. Here is a link to the study: https://www.semanticscholar.org/paper/Fat-and-carbohydrate-overfeeding-in-humans%3A-differ-Horton-Drougas/cfd2e37527960bd37f0e011c7e0e3aca55eee9ee
 
Research into de novo lipogenesis, the conversation of carbohydrates to body fat, suggests that most of the body fat on a person's body likely comes from dietary fat and not dietary carbohydrates, so the results of the study aren't surprising.
 
Also, if you look at the issue from an anthropological perspective, high-carb, low-fat cultures (ie. Japan and other Asian cultures) have much lower rates of obesity than Western countries in which many people eat diets combining a lot of carbs with a lot of fat (pizza, pasta with cheese, hamburgers, cake, etc.).
 
 
 
Once again, I'm not saying that a low-carb diet won't work: it definitely can. However, the scientific research indicates that carbs may not actually be the enemy: the enemy may actually be COMBINING high-carb WITH high-fat.

As @Rudynate said, opinion is varied. Personally, I do not think that it is necessarily bad...but it is not better than post-prandial (fed) cardio:
 
The theory makes sense: if your body doesn't have fuel in the form of recently-consumed food, you will tap into your body's fat stores for fuel. However, the scientific literature indicates that:
 
1. There seems to be some sort of "metabolic adaptation" if you eat and then exercise, your metabolism staying elevated after exercise if you eat before doing cardio.
2. Doing cardio on an empty stomach is likely to increase cortisol levels, a hormone which can make fat loss difficult if levels are too high.
3. Eating before exercising will give you more energy, thus enabling you to burn more calories. They may not all be from fat since you are in a fed state, but trying to target a certain fuel source is very difficult given the complexity of human physiology.
 
Furthermore, a 2014 study published in the Journal of the International Society of Sports Nutrition divided women into two groups: empty stomach cardio and fed cardio. At the end of the study, women in both groups had lost weight, but there was no difference between the two groups.
Link: https://jissn.biomedcentral.com/articles/10.1186/s12970-014-0054-7
 
 
Once again, I'm not saying that cardio on an empty stomach is "bad." A LOT of people have lost weight by doing it--it was especially popular during the "Golden Era" of bodybuilding. However, the research seems to show that it doesn't really matter when you do it--and that trying to theorize how hormone levels at different times of the day are going to affect fat oxidation is extremely difficult given the amazing complexity of the human body.
 
As long as you do your cardio consistently and eat to be in a caloric deficit, it doesn't really matter.

A lot of good comments here. I'll add mine:
 
I think that what @Eric Hassan said is very important: counting not only calories but also macronutrient ratios (protein, carbs, and fat) is very important for two reasons:
 
1. Not all foods have the same number of calories. There are some foods of which you can eat a lot and not eat that many calories; however, other foods, even "healthy" foods, can be very high in calories. For example, if you Google the nutrition information for 100 gram servings of foods, you will see that per 100 grams:
 
Tomato: 18 calories
Apple: 52 calories
Banana: 89 calories
 
 
As you can see, for the same amount of food (as weighed in grams), you can eat a lot more tomato and apple than banana. That doesn't mean that you shouldn't eat bananas if you want to lose weight: you definitely can (they are a good source of potassium, inexpensive, always in-season, etc.), you just have to be aware that they are more calorific than almost all other fruits and vegetables.
 
2. Even though a lot of people have had success with low-carb diets, the scientific research actually suggests that your body more easily stores a fat surplus than a carbohydrate surplus. In fact, there is a study published in the American Journal of Clinical Nutrition showing that in a 14-day study in which people were purposefully overfed calories, one group overfed with carbohydrates and the other overfed with fat, the group overfed with fat gained MORE bodyfat than the carbohydrate group. The difference was especially pronounced in the beginning of the study since humans have to fill up their muscle glyocgen stores in order to convert a significant amount of carbohydrates to body fat. Here is a link to the study: https://www.semanticscholar.org/paper/Fat-and-carbohydrate-overfeeding-in-humans%3A-differ-Horton-Drougas/cfd2e37527960bd37f0e011c7e0e3aca55eee9ee
 
Research into de novo lipogenesis, the conversation of carbohydrates to body fat, suggests that most of the body fat on a person's body likely comes from dietary fat and not dietary carbohydrates, so the results of the study aren't surprising.
 
Also, if you look at the issue from an anthropological perspective, high-carb, low-fat cultures (ie. Japan and other Asian cultures) have much lower rates of obesity than Western countries in which many people eat diets combining a lot of carbs with a lot of fat (pizza, pasta with cheese, hamburgers, cake, etc.).
 
 
 
Once again, I'm not saying that a low-carb diet won't work: it definitely can. However, the scientific research indicates that carbs may not actually be the enemy: the enemy may actually be COMBINING high-carb WITH high-fat.

I’m at the gym 6 days a week - 4 lifting, 2 cardio. I go on an empty stomach every single time. My workout is at the end of my fast so my stomach is as empty as it gets. I do consume a BCAAs before my workout, but at 20 calories, it’s not breaking my fast.
 
I’ve never been overweight (since puberty - I was a chunky boy) or had a lot of fat to lose, but I can say I’m leaner, stronger, and more defined and have more endurance (on average) since I began intermittent fasting and working out on an empty stomach about 2 years ago. I’m in sniffing range of 40 and have been working out for about 16 years now and can say most of the progress I’ve made towards what I look like today has happened in the past 2 years.
 
The question was is cardio on an empty stomach better for fat loss. I can’t say for certain but I can point to my own anecdotal evidence above. Really, though, trying to figure out the answer may be a waste of time. What you eat is going to make the biggest difference. I can understand the drive to make the choices that will provide maximal return on effort, but I don’t believe any form of self-care is a bad thing, and whether your tummy is rumbling on the treadmill or not isn’t going to matter at all if you don’t eat properly, drink lots of water, and get adequate rest.
 
If you’re thinking of doing cardio on an empty stomach, I would recommend getting some of those little energy gel packs and bring an apple. If you start feeling weak or dizzy, stop and sit. Drink water and eat the gel packet and apple. SLOWLY so you don’t puke.
 
Also, please note that I’m speaking from my own experience and medical education (I’ve mentioned before that my first career was occupational therapy), but I’m not a doctor, and even if I were, I’m not your doctor, so don’t do anything without consulting a doctor.

As @Rudynate said, opinion is varied. Personally, I do not think that it is necessarily bad...but it is not better than post-prandial (fed) cardio:
 
The theory makes sense: if your body doesn't have fuel in the form of recently-consumed food, you will tap into your body's fat stores for fuel. However, the scientific literature indicates that:
 
1. There seems to be some sort of "metabolic adaptation" if you eat and then exercise, your metabolism staying elevated after exercise if you eat before doing cardio.
2. Doing cardio on an empty stomach is likely to increase cortisol levels, a hormone which can make fat loss difficult if levels are too high.
3. Eating before exercising will give you more energy, thus enabling you to burn more calories. They may not all be from fat since you are in a fed state, but trying to target a certain fuel source is very difficult given the complexity of human physiology.
 
Furthermore, a 2014 study published in the Journal of the International Society of Sports Nutrition divided women into two groups: empty stomach cardio and fed cardio. At the end of the study, women in both groups had lost weight, but there was no difference between the two groups.
Link: https://jissn.biomedcentral.com/articles/10.1186/s12970-014-0054-7
 
 
Once again, I'm not saying that cardio on an empty stomach is "bad." A LOT of people have lost weight by doing it--it was especially popular during the "Golden Era" of bodybuilding. However, the research seems to show that it doesn't really matter when you do it--and that trying to theorize how hormone levels at different times of the day are going to affect fat oxidation is extremely difficult given the amazing complexity of the human body.
 
As long as you do your cardio consistently and eat to be in a caloric deficit, it doesn't really matter.

A lot of good comments here. I'll add mine:
 
I think that what @Eric Hassan said is very important: counting not only calories but also macronutrient ratios (protein, carbs, and fat) is very important for two reasons:
 
1. Not all foods have the same number of calories. There are some foods of which you can eat a lot and not eat that many calories; however, other foods, even "healthy" foods, can be very high in calories. For example, if you Google the nutrition information for 100 gram servings of foods, you will see that per 100 grams:
 
Tomato: 18 calories
Apple: 52 calories
Banana: 89 calories
 
 
As you can see, for the same amount of food (as weighed in grams), you can eat a lot more tomato and apple than banana. That doesn't mean that you shouldn't eat bananas if you want to lose weight: you definitely can (they are a good source of potassium, inexpensive, always in-season, etc.), you just have to be aware that they are more calorific than almost all other fruits and vegetables.
 
2. Even though a lot of people have had success with low-carb diets, the scientific research actually suggests that your body more easily stores a fat surplus than a carbohydrate surplus. In fact, there is a study published in the American Journal of Clinical Nutrition showing that in a 14-day study in which people were purposefully overfed calories, one group overfed with carbohydrates and the other overfed with fat, the group overfed with fat gained MORE bodyfat than the carbohydrate group. The difference was especially pronounced in the beginning of the study since humans have to fill up their muscle glyocgen stores in order to convert a significant amount of carbohydrates to body fat. Here is a link to the study: https://www.semanticscholar.org/paper/Fat-and-carbohydrate-overfeeding-in-humans%3A-differ-Horton-Drougas/cfd2e37527960bd37f0e011c7e0e3aca55eee9ee
 
Research into de novo lipogenesis, the conversation of carbohydrates to body fat, suggests that most of the body fat on a person's body likely comes from dietary fat and not dietary carbohydrates, so the results of the study aren't surprising.
 
Also, if you look at the issue from an anthropological perspective, high-carb, low-fat cultures (ie. Japan and other Asian cultures) have much lower rates of obesity than Western countries in which many people eat diets combining a lot of carbs with a lot of fat (pizza, pasta with cheese, hamburgers, cake, etc.).
 
 
 
Once again, I'm not saying that a low-carb diet won't work: it definitely can. However, the scientific research indicates that carbs may not actually be the enemy: the enemy may actually be COMBINING high-carb WITH high-fat.

A lot of good comments here. I'll add mine:
 
I think that what @Eric Hassan said is very important: counting not only calories but also macronutrient ratios (protein, carbs, and fat) is very important for two reasons:
 
1. Not all foods have the same number of calories. There are some foods of which you can eat a lot and not eat that many calories; however, other foods, even "healthy" foods, can be very high in calories. For example, if you Google the nutrition information for 100 gram servings of foods, you will see that per 100 grams:
 
Tomato: 18 calories
Apple: 52 calories
Banana: 89 calories
 
 
As you can see, for the same amount of food (as weighed in grams), you can eat a lot more tomato and apple than banana. That doesn't mean that you shouldn't eat bananas if you want to lose weight: you definitely can (they are a good source of potassium, inexpensive, always in-season, etc.), you just have to be aware that they are more calorific than almost all other fruits and vegetables.
 
2. Even though a lot of people have had success with low-carb diets, the scientific research actually suggests that your body more easily stores a fat surplus than a carbohydrate surplus. In fact, there is a study published in the American Journal of Clinical Nutrition showing that in a 14-day study in which people were purposefully overfed calories, one group overfed with carbohydrates and the other overfed with fat, the group overfed with fat gained MORE bodyfat than the carbohydrate group. The difference was especially pronounced in the beginning of the study since humans have to fill up their muscle glyocgen stores in order to convert a significant amount of carbohydrates to body fat. Here is a link to the study: https://www.semanticscholar.org/paper/Fat-and-carbohydrate-overfeeding-in-humans%3A-differ-Horton-Drougas/cfd2e37527960bd37f0e011c7e0e3aca55eee9ee
 
Research into de novo lipogenesis, the conversation of carbohydrates to body fat, suggests that most of the body fat on a person's body likely comes from dietary fat and not dietary carbohydrates, so the results of the study aren't surprising.
 
Also, if you look at the issue from an anthropological perspective, high-carb, low-fat cultures (ie. Japan and other Asian cultures) have much lower rates of obesity than Western countries in which many people eat diets combining a lot of carbs with a lot of fat (pizza, pasta with cheese, hamburgers, cake, etc.).
 
 
 
Once again, I'm not saying that a low-carb diet won't work: it definitely can. However, the scientific research indicates that carbs may not actually be the enemy: the enemy may actually be COMBINING high-carb WITH high-fat.

There are "blue zones" around the world where people tend to have very long life expediencies...and the people tend to be thin, too: Okinawa is one of them.
 
Although the diets vary, they tend to be:
 
1. Higher in carbohydrates
2. Lower in saturated fat, higher in monounsaturated fat
3. Often have cultured dairy
 
However, health and body composition are not one in the same: if you are in an energy surplus, you will gain weight...if you are in an energy deficit, you will lose weight. There are some competitive bodybuilders who use IIFYM (If It Fits Your Macros), a style of dieting in which you can eat whatever you want as long as you hit your calorie and macronutrient goals for the day, in order to get ready for their competitions. Pop-tarts are symbolic of this style of dieting. Is this style of dieting the best way to go about it? Probably not,...but even if you eat chicken breast, brown rice, broccoli, and olive oil every day...you won't have abs if you eat too much of it.
 
IE: Traditionally, sumo wrestlers frequently ate a stew called "chanko nabe," consisting of chicken meatballs, seafood, and vegetables. They normally drank a lot of beer, too. However, they did not eat pizza, cake, and ice cream...yet they still were not what most people would call "aesthetic."
 
Like I already said, you can lose weight on any diet...and you can also gain weight on any diet: it's just that some diets are more conducive to one or the other.

There are "blue zones" around the world where people tend to have very long life expediencies...and the people tend to be thin, too: Okinawa is one of them.
 
Although the diets vary, they tend to be:
 
1. Higher in carbohydrates
2. Lower in saturated fat, higher in monounsaturated fat
3. Often have cultured dairy
 
However, health and body composition are not one in the same: if you are in an energy surplus, you will gain weight...if you are in an energy deficit, you will lose weight. There are some competitive bodybuilders who use IIFYM (If It Fits Your Macros), a style of dieting in which you can eat whatever you want as long as you hit your calorie and macronutrient goals for the day, in order to get ready for their competitions. Pop-tarts are symbolic of this style of dieting. Is this style of dieting the best way to go about it? Probably not,...but even if you eat chicken breast, brown rice, broccoli, and olive oil every day...you won't have abs if you eat too much of it.
 
IE: Traditionally, sumo wrestlers frequently ate a stew called "chanko nabe," consisting of chicken meatballs, seafood, and vegetables. They normally drank a lot of beer, too. However, they did not eat pizza, cake, and ice cream...yet they still were not what most people would call "aesthetic."
 
Like I already said, you can lose weight on any diet...and you can also gain weight on any diet: it's just that some diets are more conducive to one or the other.

Ive heard alot about the asian diet and plant based diet lately.

My diet is higher and carbs and lower in fats.
 
I'm not sure if this is the place to go into detail, but my research suggests that a higher carb / lower fat diet is likely better for maintaining a low body fat percentage.
 
From an anthropological standpoint, look at Asian cultures: a lot of rice, vegetables, and some fruit. In fact, the traditional Okinawan diet was based on a purple sweet potato, about 80% of their daily calories coming from carbohydrates,...and along with many other Asian cultures, the people were thin (average BMI of around 20 in adulthood on Okinawa in 1950).
 
With that said, I think that "a lot of roads lead to Rome" when it comes to dieting, and it's important to remember that NO DIET will work unless you are in an energy deficit.
 
 
So, whatever diet you choose, as long as you don't consume more energy than you burn, you will stay thin.