Fasted cardio is having a moment. Wake up and get your exercise in before breakfast, so the theory goes, and your body will be forced to burn fat, because there will be no food in your stomach to use for fuel. But does fasting before a workout actually make a difference to your weight, or your health? Not the way you’d think. Let’s take a look at the science.

What is fasted cardio? 

“Fasted” cardio doesn’t require some kind of extreme starvation protocol. It just means doing cardio when you haven’t eaten recently. The most common way to do fasted cardio is to work out first thing in the morning, before breakfast, since you’ve been fasting all night. (The word “breakfast” even comes from the fact that the first thing you eat is breaking your fast.)

Cardio refers to any movement you can do rhythmically for minutes or hours on end, like jogging, cycling, swimming, or using gym machines like a stepper or an elliptical. So if you’ve ever gone for a morning jog without having a snack first, you’ve already done fasted cardio. 

Does fasted cardio help you burn fat? 

In a limited, technical sense: maybe. In a real-world, big-picture sense: no. 

Remember that we are all burning fat all the time, just by existing. How do you think your body stays alive all night while you are sleeping? It burns through a little bit of your fat stores, knowing that during the day you will eat more food and it will be able to replace that fat. 

In other words, there is a difference between burning fat and losing fat. We burn fat and replace it continuously throughout the day; burning fat doesn’t mean losing fat. We only lose fat when we don’t eat enough to replace all the fat that we burned. 

Ultimately, you don’t have to pay attention to what fuel your body is using at what time. If you really want to nerd out about the details, your body has carb stores as well (called glycogen), and you burn through those stored carbs when you do fasted cardio—so the energy you use isn’t all coming from fat anyway. 

What the science says about fasted cardio

Scientists have tested the possibility that fasted cardio might lead to fat burning, which in turn might lead to fat loss. Unfortunately, the results are pretty clear that fasted cardio does not seem to help people lose weight. 

In this 2014 study, 20 women were put on a calorie-restricted diet (which would help them lose weight), and did an hour of cardio three mornings each week. Half the women got a shake before their cardio session, and half got the shake after. Members of each group were eating the same number of calories each day in total. 

The results? Both groups lost the same amount of weight. Fasted cardio provided no additional benefit. 

It’s not even clear whether fasted cardio increases fat burning. A 2018 meta-analysis found that 38% of studies on fasted cardio found more free fatty acids in the bloodstream when compared to fed cardio; that means that fat was being burned. But one 2011 study actually found that fat burning was greater among people who ate before they did their cardio. Based on these results, I wouldn’t trust fasted cardio to burn more fat, much less lose it.

The downsides of fasted cardio

The biggest downside of fasted cardio is that you’ll almost always perform better during a workout when you’re fed. You’ll be able to push harder, work longer, and feel less tired doing it. If you find exercise to be exhausting, a pre-workout meal, snack, or even a sports drink may change that. 

Longer sessions will especially benefit from eating beforehand. It’s well-known among endurance athletes that marathons, all-day bike rides, and lengthy hikes benefit from a hefty supply of calories, mainly in the form of carbs. If you’re exercising for more than an hour at a time (some say more than 90 minutes) you should not only eat beforehand, but also bring fuel with you to eat on the go. 

At the extreme end, going without food during exercise can leave you felling dizzy or lightheaded (especially if you are pregnant or have medical issues that can affect your blood sugar). It can also mean “hitting the wall” after a few hours—that point you reach where your body doesn’t have enough stored carbs to keep up the level of effort you’re aiming for. (This is more of an issue for marathoners than for casual joggers, so don’t let that scare you off if you’re just figuring out fueling for a short morning run.)

When fasted cardio can make sense

Even though I sing constantly the praises of pre-workout carbs, I do a lot of fasted cardio myself. I don’t do it for fat burning benefits; I do it because I jog in the morning and I don’t want to bother finding the time to eat beforehand. 

It may make sense to do cardio on an empty stomach if:

• You have a sensitive stomach, and might get nauseous if you eat right before you run.

• You don’t have time to eat beforehand, and your workout will be a short or easy one anyway.

• You have a limited calorie budget for the day, and want to save your carbs for later (before an evening weightlifting workout, perhaps). 

In these cases, I would only skip the pre-workout meal if your cardio session will be a relatively short or easy one. Long sessions still require fueling. If stomach discomfort is the issue, consider eating a meal a few hours beforehand—or even have a filling dinner or midnight snack before a long or hard morning run. It’s also worth figuring out whether there might be small snacks, like a banana or a swig of sports drink, that can give you some fuel before your run without triggering your stomach issues. 

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Prime Day is almost here, and to make the most of the big sale, you need to be an Amazon Prime member. This typically costs $139 per year or $14.99 per month, and comes with a lot of perks, like faster shipping on many items and access to Prime Video streaming.

Amazon used to let you share all those membership benefits with a limited number of people, but last year the company tightened up the rules, replacing the old system with the Amazon Family program. Now it comes with a lot more restrictions, but there are still ways around them—as long as you’re okay with the drawbacks.

Sharing Prime benefits with Amazon Family

Amazon Family is the existing program for sharing Prime benefits, and it allows you to add separate profiles for one other adult who lives in the same household as the primary account holder, and up to four kids. This grants access to all the standard benefits, such as free delivery, Prime Video with ads, Prime Reading, third-party benefits like Grubhub, and access to audiobooks, e-books, certain games, and Amazon Music.

However, there is still a way to share your Prime benefits with anyone, regardless of whether they live in the same household.

How to share Amazon Prime benefits with anyone

If you want to share benefits with people outside of your household, you still can—with a big caveat. I’ve been using my parents’ Prime account for years, simply by logging in with their email and password. This comes with the inconvenience of mixing order histories and payment methods, but it is a simple way to share a Prime subscription without restrictions—I can use it even while living in a different state, as can my siblings.

The biggest potential issue here is that you will occasionally need to share one-time temporary passwords (OTP) from the primary account holder when you log into a new device (or get logged out for some reason). OTPs can also be required when trying to change certain subscription settings.

To keep things somewhat separated, you can still create separate profiles under the same Amazon Prime login, but you’ll still all have access to the same order history, addresses, payment methods, subscriptions, returns info, etc. As long as you’re cool with that from a privacy standpoint, it’s no hassle, though you will need to pay extra attention—I’ve messed up a few times and sent orders to one of my family members’ homes or used their credit cards, and vice versa.

Given that many people won’t be comfortable with all of the above, it’s no real surprise that Amazon has yet to address this workaround, though that’s no guarantee the company won’t make it harder (or impossible) to share logins this way in the future.

AI is everywhere right now—even in places you don’t expect. You might be jamming to a new song on Spotify or YouTube, only to later learn that the track was “composed” entirely by bots (save for an initial human-generated prompt). Some might argue that AI music has its place, but if you’re like me, you want to devote your attention to art created by real people, who have taken the time to hone a craft and share it with the world. And while I believe AI music can never replace that, the fact is, it’s getting more difficult to identify these tunes when we come across them in the wild.

To be fair, some companies have been working on ways to identify AI content on their platforms, notably Spotify, YouTube, and Apple Music. But while you might come across an AI label here and there, there are still plenty of examples of AI-generated content that aren’t identified as such—in part, because much of the reporting is still based on the honor system. Lifehacker’s David Nield was frustrated by that experience when looking for music to listen to on YouTube, and found the only reliable solution was to do some research before committing to any particular channel. He now has a shortlist of options to choose from, sure, but it’s a lot of work to guarantee your music selection is 100% human-made. It also makes it harder for small creators, who might not have as much “proof” that they aren’t using AI, if you’re this strict with your consumption.

How to use Deezer’s new AI detector

Deezer, a French music streaming service, thinks it has a solution. As reported by MacRumors, the platform now has a new tool it says can identify AI-generated music with nearly 100% accuracy. The company says that it receives over 75,000 AI-generated songs every day, which amounts to 44% of the total uploads to the platform. By looking for artifacts left behind by AI, Deezer claims it can spot whether the track was made by humans or bots. In fact, it seems that the tool is the same Deezer uses to label AI tracks on its own platform.

Of course, this tool works with Deezer itself, so if you’re a user, you already have access. But the company says its AI detector works with as many as 20 different streaming services. That includes the following:

• Spotify

• Apple Music

• YouTube

• YouTube Music

• Tidal

• Amazon Music

• Soundcloud

• Yandex Music

• Qobuz

• Beatport

• iTunes

• Napster

• Pandora

• Anghami

• KKBOX

• Last.fm

• Soundmachine

• Boomplay

• Audiomack

In order to use the tool, you need to connect it to your streaming service of choice. That might rub privacy-minded users the wrong way since you need to give a third-party tool access to your streaming service, but if you’re okay with Deezer accessing your Apple Music or Spotify libraries, you can take advantage of the detection software. Alternatively, you can manually connect Deezer’s detector to playlists if you have the link (but you can’t upload individual tracks). Once you connect Deezer to your platform, it imports your various playlists and looks for any music it thinks was made using AI.

Deezer claims its tool is 99.8% accurate and misses two out of every 1,000 tracks. There’s no real way to test those stats, however, so take them with a grain of salt. I also wish the detector was a bit more flexible. I’d love not to have to connect my entire streaming service to use it, and I would like to have the option to test more than just individual playlists. I think an AI detector would be most useful on a case-by-case basis, rather than when questioning whether part of your playlist contains AI-generated tracks. Still, a tool like this may be a powerful ally in the battle to listen to human-made music—or, at the very least, know for certain that the song you’re enjoying was generated with AI.