Does Athletic Greens (AG1) break a fast? Explained by Simple
Athletic Greens* — or AG1 — is a supplement known for its nutrient density.
But does Athletic Greens break a fast?
Here’s the 4-1-1 on Athletic Greens and whether it can interfere with your intermittent fasting intermittent fasting goals.
Does AG1 break a fast?
What to know about Athletic Greens and intermittent fasting.
Does drinking AG1 break a fast?
There’s no universal answer to “does drinking AG1 break a fast?”
It comes down to you, your fasting protocols, and your goals.
The recommended serving of AG1 contains more than 10 calories, which is often the accepted benchmark for how many calories you can consume during a fasting window without raising insulin levels and breaking a fast. So yes, if you’re following this strict, calorie-free definition of fasting, then Athletic Greens does break a fast.
But we’re all unique individuals, and our bodies, metabolism metabolism , and responses to supplements vary. You may not need such a strict calorie cut-off during your fasting window to see results related to energy, health, or diet quality.
That’s why we always recommend consulting your healthcare provider rather than trying to decide “Will Athletic Greens break my fast?” on your own. They’re best placed to assess whether intermittent fasting is appropriate for you in the first place and how supplements may affect your body. (This is especially important if you’re considering intermittent fasting to help with insulin resistance or other existing health conditions.)
Understanding fasting protocols
Not all fasting protocols follow the same rules, which is why the question “does AG1 break a fast?” depends on context. Some people practice intermittent fasting using time restricted feeding, where eating is limited to a set eating window each day. Others follow alternate-day fasting or longer fasts for metabolic or clinical reasons.
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In stricter fasting protocols, even small amounts of calories, carbohydrates, protein, or sugar may technically break a fast.
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In more flexible approaches, small amounts of calories from supplements may be acceptable if they don’t meaningfully affect energy balance, digestion, or the effectiveness of fasting on your goals.
The key point is this: fasting protocols are tools, not tests of willpower. What matters most is whether your approach moves your nutrition, weight goals, and overall health in the direction you want.
If you’re feeling a little bamboozled by all the fasting options at your fingertips, we’re here to help. From general advice on what to eat or drink during your fasting window and eating window (check our guide: what you can drink while fasting for a deep dive into beverages) to personalized recommendations tailored to your specific fasting goals, we’re here to provide all the support you need. Take our quiz to get started.
What is Athletic Greens?
AG1 is a daily multi-nutrient supplement containing over 70 ingredients, including vitamins, minerals, probiotics, and plant compounds derived from fruits and vegetables. It’s formulated to deliver broad nutritional coverage in one serving.
AG1 comes in a water-soluble powder and is NSF-certified for sport, meaning it doesn’t contain banned substances and meets quality standards for competitive athletes.
How many calories are in Athletic Greens?
One scoop (12 g serving) of AG1 contains approximately 50 calories, including:
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6 g of carbohydrates
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2 g of protein
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2 g of fiber
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0 g of fat
plus a complex mix of vitamins, minerals, antioxidants, and digestive enzymes.
The calories in AG1 come from ingredients such as plant extracts, fiber, and protein, and is low in sugar with zero artificial sweeteners.
However, from a fasting perspective, calories are still calories, regardless of source. And, because AG1 contains carbohydrates, protein, and fiber, it can stimulate both insulin insulin and digestion, which technically breaks a fast under most definitions.
Health benefits and possible drawbacks of using Athletic Greens while intermittent fasting
If you do choose to drink Athletic Greens while fasting, there are some benefits and drawbacks to look out for.
The nutrients inside AG1 — as opposed to AG1 itself — may support health benefits often associated with intermittent fasting, including:
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improving heart health, metabolic health, and gut health [1,2,3]
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boosting your immune system [4]
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supporting cognition and concentration [5]
But you don’t necessarily need a supplement to access these benefits. All of the nutrients found in Athletic Greens are found naturally in many whole foods, like fruits, vegetables, and whole grains — and the benefit of getting these nutrients through whole food sources is that you’ll likely absorb them better and get other nutrients from the food, too.
Plus, Supplements don’t agree with everyone.[6] For instance, while certain probiotics probiotics or prebiotics in AG1 might relieve digestive comfort for some, they may also cause bloating or cramps for others.
While AG1 may help close nutritional gaps for some people, it doesn’t replace a balanced diet. Talk with your healthcare provider to explore if adding supplements is right for you.
Common mistakes to avoid
When combining intermittent fasting and supplements like Athletic Greens, problems often come when expectations don’t match reality, creating confusion or frustration. Some common mistakes include:
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Expecting a single clear rule to apply to everyone. Fasting isn’t one-size-fits-all, and neither are supplements, which affect different bodies in different ways. What feels disruptive for one person may be neutral for another.
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Over-focusing on the supplement itself. It’s easy to zoom in on whether Athletic Greens breaks a fast and miss the bigger picture of your overall diet, habits, and consistency.
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Letting fasting or food rules override how you feel. Strict rules often lead people to ignore hunger cues, energy levels, or body signals that matter more long term.
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Using supplements to “optimize” too early. If your meals, eating window, or food quality aren’t dialed in yet, adding supplements probably won’t deliver the results you expect.
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Trying to self-diagnose instead of asking for help. Fasting and supplements can interact with medications or health conditions, so professional guidance is essential if you are taking medication and/or dealing with a health condition.
Tips on using Athletic Greens during a fast
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Consult your doctor. When mixing intermittent fasting and supplements, it’s not always clear which supplements will affect your fast — or your body, or your health. Some supplements may not be right for you. So, talk to your healthcare team “Is taking Athletic Greens safe for me?” before you get into “Can I take Athletic Greens while fasting?”
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Take Athletic Greens at the start of an eating window. Forget the stress of wondering, “Does Athletic Greens break a fast?” by eliminating it from your fasting window and drinking plain water instead. Taking Athletic Greens on an empty stomach is recommended for better nutrient absorption, and at Simple, we’re fans of breaking your fast and starting your eating window with something nutrient dense and easy to digest. Athletic Greens could be a great fit here. However, it’s also great to break your fast using whole foods. The choice is yours!
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Fill up on nutrient-dense foods. Prioritize getting as many nutrients from natural sources as you can. If you’re getting everything you need from what you eat, you likely don’t need AG1. Check out our guide on what to eat during intermittent fasting for ideas.
Frequently asked questions
Does Athletic Greens break a fast?
Yes, Athletic Greens does break a fast under many fasting protocols because it contains calories, carbohydrates, protein, vitamins, minerals, and other substances that stimulate digestion. One serving contains 6 g of carbohydrates and 2 g of protein, which is enough to raise insulin levels for many people.
Will AG1 stop autophagy during fasting?
It may. Because AG1 contains carbohydrates, protein, and calories, it can interfere with metabolic processes linked to fasting, including autophagy. If you’re following a strict fasting protocol for cellular health goals, it’s usually best to wait until your eating window opens before taking supplements.
How many carbs are in AG1?
AG1 contains 6 g of carbohydrates per serving, including less than 1 g of naturally occurring sugar. It also contains 2 g of protein. For people wondering whether carbs in supplements break a fast, this amount is usually considered high enough to break stricter fasts.
Can I take AG1 during time restricted feeding?
Yes, but many people practicing time restricted feeding choose to take AG1 during their eating window instead of while fasting. This helps you absorb the vitamins and minerals in the supplement without worrying about whether Athletic Greens breaks your fast.
Do supplements always break a fast?
Not always. Whether supplements break a fast depends on the ingredients, calories, carbohydrates, and your fasting goals. Some supplements contain almost no energy, while others — like AG1 — contain enough carbs and protein to disrupt stricter fasting protocols.
Is AG1 low in sugar?
Yes. AG1 is low in sugar and contains less than 1 g of naturally occurring sugar per serving. But even low-sugar supplements can still break a fast if they contain enough carbohydrates, protein, or calories to stimulate digestion and insulin response.
*While we use the name Athletic Greens throughout this article for ease of understanding, it’s important to note that Athletic Greens is a registered trademark of Athletic Greens International, Inc. To learn more about Athletic Greens and its products, feel free to visit their website at https://drinkag1.com/.