Does Caffeine Really Stimulate Fat Loss?

Billions of people around the world drink coffee or tea to start the day. It’s a good way to get the engine running. The kick, of course, is due in large part to the caffeine content in these drinks. Caffeine is a powerful stimulant and appetite suppressant, but you probably already knew that.

Less commonly discussed, however, are the effects of caffeine on body composition. Sure, caffeine wakes you up in the morning, but can it burn fat? Does it help with weight loss? In fact, it can. Caffeine has been shown to stimulate fat loss, help with weight management, and enhance exercise. If you’re trying to optimize your body composition, caffeine should probably be in your weapons.

But before we get to practical advice on incorporating caffeine into your routine, let’s talk about the mechanisms by which caffeine stimulates fat loss.

How caffeine burns fat?

First of all, what exactly does it mean to burn fat? Clearly no one is holding your fat cells to a burning flame. That would feel awkward at all costs. Instead, burning fat is synonymous with using fat for energy. And fat can only be used for energy when it’s floating around the bloodstream in a molecule called free fatty acid.

However, what most people think of when they hear the word “fat” is not the free fatty acid form of fat. No, they think of adipose tissue, or fat cells that contain these fatty acids. In order to lose overall body fat, you have to tell your fat cells to release these fatty acids.

So how can you increase the release of fatty acids to be burned? One way is caffeine!

The caffeine in your morning coffee stimulates the breakdown of fat tissue through a process called lipolysis. And once the fatty acids are released from their storage form, they can be used for energy. In other words, this fat can be burned.

How does caffeine stimulate lipolysis? When you drink caffeine, the levels of energy hormones such as epinephrine and norepinephrine increase in the blood. These hormones, in turn, cause the release of fatty acids.

Caffeine increases your metabolism

Okay, now you know that caffeine stimulates lipolysis. And we know that lipolysis causes fatty acids to be released into the blood. And now that?

Well, fatty acids must be burned for energy. And the process of burning energy is called metabolism. Depending on your diet, lifestyle, and genes, your metabolism may burn energy at a higher or lower rate.

What is a compound that stimulates our metabolism to burn more energy? You guessed it again: caffeine.

This metabolic spending process has a fancy scientific name: thermogenesis. Caffeine increases thermogenesis. In other words, it tells your body to burn more calories.

This stimulating effect on metabolism has in fact been shown through research to occur in humans. In this study, caffeine increased thermogenesis in a dose-dependent manner up to 400 mg, or about 2-3 cups of coffee. More information on dosing later.

In a more recent study, caffeine increased the metabolic rate of human cells by activating certain genes associated with metabolism. So even at the level of your genes, there is clearly an effect of caffeine on energy expenditure.

What about caffeine and weight loss?

By now you are probably wondering how caffeine-induced thermogenesis and lipolysis translate into real, measurable results in humans. These cellular processes sound good, but do they really stimulate measurable weight loss?

It looks like it is. In one study, 76 overweight volunteers – a mix of high caffeine and low caffeine consumers – were put on a low calorie diet for 4 weeks. Weight was a primary variable that was being measured.

The results? At the end of the four-week period, greater weight loss was associated with greater caffeine intake in women. Not a bad benefit of drinking an extra cup of coffee or two.

But wait, there is more. In a large 2016 observational study, people who drank the most caffeine were also more likely to have weight loss maintenance success. So for those struggling to maintain losses from a diet or exercise program, caffeine could provide helpful support.

One final note on caffeine and weight loss: the research is promising, but still correlational. In other words, there are no adequate controlled experiments showing caffeine alone causes people to lose weight, but it appears to have some weight loss benefit.

Caffeine improves exercise

Most people know that exercise is a scientifically validated way to burn fat, increase lean muscle, and improve body composition. Take all the supplements you want – you’re not going to look good naked from sitting on the couch all day.

Good, so you are aware that exercise is important. But to take it up a notch and enhance the effects of that workout, consider caffeine.

From a metabolic standpoint, combining caffeine with exercise is like putting premium fuel into a European sports car. It just works better than regular unleaded in the tank.

For example, having caffeine in the system during intense aerobic exercise increases the availability of free fatty acids and more than doubles epinephrine levels. It also seems to improve fat burning. Finally, in some individuals, caffeine spares muscle glycogen – probably useful for athletes trying to conserve energy during longer bouts of exercise.

Caffeine is also ergogenic, meaning it improves exercise performance.

We just covered how combining exercise with caffeine puts your body into fat burning mode. However, there are, in fact, other positive effects that arise from this combination.

First, even in low doses (about 1-2 cups of coffee), caffeine improves mood, cognitive function, and alertness during and after exercise with very few side effects. So if you feel sluggish during your workouts, caffeine can help.

What types of exercise does caffeine improve?

There are 3 main categories:

  • Resistance Training – Several studies have shown promising results by adding caffeine to resistance exercise. In a randomized crossover trial, a small group of cyclists had significantly faster performance times when given caffeine than when given decaffeinated coffee. Another study found that any dose of caffeine – low, medium, or high – improved endurance times by about the same amount.
  • Strength and Power – Caffeine also improves strength. In one study, caffeine significantly increased the maximum force of muscle contraction in a group of endurance athletes. In another, it increased upper body strength in resistance-trained women.
  • High intensity efforts – Finally, caffeine improves muscle energy status during intense exercise. In some individuals, it also spares muscle glycogen.

The point here is that caffeine appears to enhance both fat burning and exercise performance. It is something that every athlete should consider including his diet.

Caffeine increases testosterone

Testosterone, the male sex hormone, is a good hormone to have around if your goals include losing fat and preserving lean muscle. In one study, people supplementing with testosterone were leaner and lost more fat than the control group.

But you don’t need testosterone patches to boost your levels of this crucial hormone. Instead, just have a cup.

Or, if you’re up for trying something a little more unconventional, chew on some caffeinated gum. In a recent study, rugby players taking caffeinated gum at half time had, by the time the 15 minute half was up, 70% higher salivary testosterone levels than their placebo gum counterparts. That is very significant.

How much caffeine do you need?

That depends on your goals. For exercise, research shows that low doses (less than 200mg of caffeine – about a large cup of coffee) are just as effective as high doses in enhancing performance.

For fat burning goals, on the other hand, it appears that the metabolic response to caffeine is increased in a dose-dependent manner. 400mg is better than 200mg is better than 100mg.

And in case you were wondering, your typical 8oz cup of coffee has 100-150mg of caffeine. For a lower dose, a cup of green tea has about 25mg of caffeine.

Caffeine Side Effects

So more caffeine equals more fat burning. Given that fact, should you drink as much strong coffee as your stomach can hold?

Not so fast. Consuming high amounts of caffeine still has some undesirable side effects, including:

  • Insomnia
  • Gastrointestinal distress
  • Nervousness
  • Confusion
  • Trouble focusing
  • Potential problems with blood pressure in hypertensive individuals

In other words, be smart about caffeine. Listen to your body. If you are experiencing anything unusual, lower the dosage.


Well, that was a lot of information. To summarize, here is a list of what caffeine has been shown to be:

  • Stimulate lipolysis, releasing fatty acids to be burned for energy
  • Increase your metabolic rate, or the rate at which your fuel is burned for energy
  • Has been shown to help with weight management, and may also help with weight loss
  • Helps promote fat burning during exercise through your metabolic process
  • Improves mood and alertness during exercise
  • Increases testosterone during exercise
  • High doses may have side effectsunwanted like insomnia or stomach problems

How many people around the world consume caffeinated beverages every morning without being aware of these benefits?

Impossible to say. Probably most of them. But now you are aware of the benefits. So if you’re looking for something to shed a little fat, boost your weight loss goals, and maybe even boost today’s gym session, don’t forget your cup of green tea or coffee tomorrow morning.