Written by Garett Reid | NSCA, CSCS, CISSN, M.S.E.S.S
Fact checked by Andrew Lenau, ISSA CPT & Sports Nutritionist
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One of the most popular nutritional supplements on the market today is fat burners, which probably shouldn't come as too much of a surprise, considering losing weight is one of the top, if not the #1 goal, for many people who go to the gym.
And ideally, if weight loss is your goal, taking fat burners and working out should go hand in hand, as together they will help you burn more calories throughout the day.
In addition, fat burners with stimulants will give you more energy to work out even harder (meaning you have the potential to burn more calories!), and establishing sound exercise habits now will help you more easily maintain your weight loss in the long run.
So, if you're taking a fat burner, it's a good idea to work out as well, as it will only help you lose more weight and keep it off in the long run. But, do you absolutely need to work out while taking fat burners? And what happens if you don't?
Let's find out.
What Is A Fat Burner?
Fat burners are a class of nutritional supplements that are used to increase fat loss. Each fat burner supplement contains a unique combination of ingredients and dosing designed to help you lose body fat.
Fat burners typically either do this by increasing your calorie burn through thermogenesis or decreasing your calorie intake by curbing hunger, leading to loss of body fat and improved body composition.
You can learn even more about fat burners in our article: What Is A Fat Burner?
What Do Fat Burners Do?
Fat burner supplements enable your body to burn fat through several mechanisms.
The most common ways fat burners help you lose weight include:
- Increase calorie burn by ramping up metabolism
- Decrease appetite and cravings
- Increase energy and physical activity levels
- Increase focus
Again, the main purpose of each of these is to burn fat.
Do Fat Burners Work?
Before we get into too much detail, let's first answer the question: Do Fat Burners Work?
And the answer is: Yes, fat burners work. Multiple studies have shown that using fat burners and thermogenic supplements effectively increases metabolism and improves body composition.
For example, a 2021 meta-analysis examined fat loss through thermogenic fat burners, comparing it to fat loss through exercise and diet¹. To be clear, the people taking dietary supplements were not exercising.
The researchers found that even without exercise or a regimented diet, people still successfully lost weight only using fat burners. However, it's important to note that the group that only took a fat burner lost less fat than the group that performed exercise and followed a healthy diet.
Other studies have also shown positive findings with taking fat burners. In 2023, a paper examined the effects of participants taking a multi-ingredient fat burner2.
The study concluded that the fat burner's thermogenic mixture resulted in an increased metabolic rate, more calorie expenditure, and reduced fatigue over a 3-hour period.
The supplement used a large number of ingredients (20+), including:
- Caffeine
- Garcinia Cambogia
- CLA
- Raspberry Ketone
Interestingly, even though there were so many ingredients used, no negative health markers were seen in the blood tests, suggesting that fat burners are safe.
What Happens If You Take Fat Burners Without Working Out?
So, what happens if you take fat burners without working out?
The effects of what happens will be determined by what ingredients are in the fat burner. This is due to the different mechanisms by which the ingredients work.
Here's a look at some potential outcomes.
1) May Cause Jitters:
Taking thermogenic fat burners can increase your heart rate and give you an energy boost. Out of all the types of fat burners, stimulant fat burners have the most noticeable effects.
When taken without exercise, stimulant fat burners may give someone the jitters or make them feel fidgety. In addition, stimulant fat burners may increase your body temperature, which can result in sweating and agitation.
Other fat burners, such as non-stimulant fat burners, will not affect you as much.
Many ingredients in non-stim fat burners work by increasing focus and concentration. Therefore, this type of fat burner may even be able to provide benefits when you're doing work or chores and may be the better choice if not training.
2) Still Mitigates Appetite:
One of a fat burner's mechanisms is to help decrease your appetite. If you're not working out, taking a fat burner can still help support your weight loss goals by preventing you from over-eating.
Eating fewer calories will play a massive role in overall body fat, so this means they can still help with your weight loss progress.
But, imagine the gains you could make if you ate less and exercised.
3) Potentially Leads to Loss Of Muscle Mass:
One final issue to address is the loss of lean muscle mass that may occur if you take fat burners and don't exercise. Whenever you put yourself in a caloric deficit, you put yourself at risk of losing muscle.
Our bodies are efficient machines, so when they need energy, they find it from various compounds, and that includes muscle.
So, if you're taking fat burners but not doing anything to preserve your muscle, you risk losing it. To avoid this, keep your calorie deficit minimal and use a workout split to preserve muscle.
Are Fat Burners Effective Without Exercise?
The answer to this question depends on what you mean when you say effective.
We need to remember that burners work independently of exercise or diet. In other words, you don't need exercise for the mechanisms of fat burners to take place. In this context, fat burners will work without exercise.
Now, if we're talking about effectiveness in terms of overall fat loss, then combining exercises with fat burners will be significantly more effective. It's the same concept with diet and exercise. A calorie-restricted diet, like this weight loss meal plan, will burn fat, but combined with an exercise plan, it will be much more effective.
In addition, if you don't work out after taking fat burners, you may be "wasting" some of the benefits of fat burners. One of the major mechanisms by which fat burners work is by increasing energy levels.
Many people will use energy boosts to help them move more and have a more intense workout. If you don't take advantage of this extra energy, you will miss out on burning additional calories.
Still, to suggest that fat burners don't work without exercise is to suggest that they, in fact, do nothing, which isn't true. Again, we can go back to the abovementioned meta-analysis that shows fat burners are effective at reducing body mass while improving cardiometabolic health.
However, this effect is smaller than either exercise alone or exercise plus diet.
Should You Take Fat Burners On Rest Days?
Absolutely! We need to be sure to distinguish fat burners from pre-workouts. A pre-workout is taken before you exercise to improve sports performance. Going to the gym and working out harder is the entire purpose of a pre-workout.
On the other hand, with fat-burning supplements, you can go to the gym after taking one, but its primary purpose is to increase metabolism and calories burned. In other words, you can go to the gym or simply perform basic life activities.
That said, you can definitely take fat burners without working out. But, remember, if you take a stimulant fat burner and then plan to be semi-inactive, it could result in you feeling jittery.
On your rest days, you may be better off taking a non-stimulant fat burner to avoid excess energy or uncomfortable side effects.
Can You Lose Weight Taking Fat Burners Without Exercise?
Absolutely. Let's remember that when losing weight, the main priority is to burn more calories than one consumes to create a caloric deficit. You will lose weight if you can make a caloric deficit.
There are two different mechanisms by which this can happen:
- You can increase your calories burned through exercise and activity.
- You can decrease the calories you consume through diet.
When looking at these two, diet is generally the most important mechanism in a person's weight loss journey. To be clear, your best bet is to do both of these, but diet will play the most significant role.
With this in mind, you can definitely lose weight by taking fat burners without working out. However, this means you must get your diet under control. If you reduce your calorie intake, a fat burner can further increase your calorie burn and your body's fat burning process.
In addition, you can utilize other strategies, such as taking a nighttime fat burner instead, which is an easy way to burn fat while you sleep.
Tips To Make The Most Of Your Fat Burner
If you have decided to use fat burners to help with your fat loss or to simply help maintain your body weight, there are some habits and guidelines that can help you optimize your fat loss.
- Follow an effective exercise program that includes resistance exercise training and cardio.
- Follow a calorie-restricted diet that is sustainable.
- Use non-stim fat burners on non-workout days.
- Use non-stim OR stimulant fat burners on workout days.
- Take fat burners 30-60 minutes before meals to mitigate overeating.
- Only take nighttime fat burners close to bedtime, as any other type can affect your sleep, and poor sleep can cause weight gain.
- Increase water intake when taking fat burners.
What Are The Best Fat Burners To Take When Working Out?
This will depend on what you're hoping your fat burner will do for you.
If your goal is to take one with stimulants that will help you exercise even harder, PhenQ is one of our favorite fat burners, containing natural caffeine and Capsimax powder to increase your energy and boost your metabolism.
PhenQ is a natural weight management system that targets 5 key areas of metabolic health to help shed excess fat, crush cravings, and support natural energy...
Instant Knockout is another great option, containing energy-boosting ingredients like green tea, caffeine anhydrous, and green coffee bean.
Looking for more great options? We've got tons!
Check out our articles on the Best Fat Burners For Men and the Best Fat Burners For Women. Looking for great stimulant-free options? We've got those too in this round-up of the Best Non Stimulant Fat Burners!
Fat Burners Burn Fat With Or Without Exercise
A quality fat burner can be helpful in your overarching weight loss journey. They can increase calories burned, improve your body's burning fat ability, decrease calories consumed, and provide increased energy levels, regardless of whether you're exercising.
However, if you are thinking of taking fat burners on rest days or aren't planning to work out on your weight loss journey, you may want to opt for less stimulating or even non-stimulant fat burners.
Particularly if you're sensitive to stimulants, taking a strong stimulant without working out could produce unpleasant side effects, such as jitters and sweating. Or, if you do want a stimulant fat burner and aren't planning to exercise, try a half dose of your fat burner to start, so you can see how you react.
Another great option? Throw in some exercise with your fat burner. You'll feel better, look better, and find you lose weight more easily!
Looking for a great fat burner? These 9 Best Non Stimulant Fat Burners are great for rest days or for those who aren't planning to exercise while taking their weight loss supplements. Or, for some stimulant options, check out the Best Fat Burners For Men and the Best Fat Burners For Women!
References:
- Clark, J. E., & Welch, S. (2021). Comparing effectiveness of fat burners and thermogenic supplements to diet and exercise for weight loss and cardiometabolic health: Systematic review and meta-analysis. Nutrition and health. https://doi.org/10.1177/0260106020982362
- Prather, J. M., Florez, C. M., Vargas, A., Soto, B., Harrison, A., Willoughby, D., Tinsley, G., & Taylor, L. (2023). The effects of a thermogenic supplement on metabolic and hemodynamic variables and subjective mood states. Journal of the International Society of Sports Nutrition. https://doi.org/10.1080/15502783.2023.2185538
Garett Reid
Author