What are the differences between macronutrients and micronutrients? This might be the most important question in nutrition: in the categories of macronutrient and micronutrient, you’ve got almost everything a human being should ingest.
To break down the science and help you work out what matters most — and to make sure you know what you should be consuming outside of these two categories — we’ve spoken to sports dietitian Natalie Rizzo, MS, RD and looked at all the research you should know about.
Macronutrients vs Micronutrients
“Macro means ‘big’ and micro means ‘small,’ it’s basically two different types of nutrients,” Rizzo begins. “Macros, there are only three of them: protein, carbs, and fats. Micronutrients are all your other nutrients that are basically vitamins and minerals, and there are tons of them: Vitamins A, B C, D, E, K, minerals are iron, calcium, sodium, potassium, all of those.”
Basically, macros are nutrients that provide calories and are measured in grams, and micros are what you usually measure in milligrams or micrograms. (Some, like Vitamin D, you measure in “International Units.”)
If you’ve ever taken a look at a diet calculator like this one, you’ll see that you’ll be given a calorie goal to hit and a macronutrient split: a number of grams of protein, carbs, and fat you should eat every day.
Getting your macro balance right is crucial for getting your ideal physique and all three are super important for your overall health. In broad strokes:
- Protein (4 calories per gram) you’ll find in large amounts in meat, eggs, dairy, and legumes, and it helps to build and repair muscle.(1)
- Carbohydrates (4 calories per gram) you’ll get in grains, fruits, starches, and they help to support energy levels and provide fiber, which improves digestive health and helps with nutrient absorption.(2)
- Fat (9 calories per gram) you’ll find in fatty meats, nuts, coconut, oils, seeds, and it’s important for hormonal health and to help you absorb nutrients.(3)
Macros have other functions as well, but these are the main bullet points. We’re Nutrition 101-ing here.
This is your vitamins and minerals, and unlike macros, they don’t have calories. They often accompany calories — if you eat yogurt, you’ll get calcium along with the protein and fat and carbs, but the calcium doesn’t have calories.
Some micros are easier to get than others. Vitamin C is so common that you can get more than a day’s worth from one orange or one cup of broccoli. A vitamin most people are deficient in is Vitamin D, which we make from sunlight and is very hard to find in foods.
“It’s one of those micros where most people should take a supplement,” says Rizzo. “Because Vitamin D is actually really important for bone health. We tend to think of calcium (as the bone health nutrient), but Vitamin D is important for that as well.”
Other micronutrients that are tricky to get in your diet include magnesium (found in leafy greens), which helps with sleep quality and stress reduction and selenium (found in nuts and seafood), an antioxidant that reduces inflammation.(4)(5)(6)(7)
Not Everything Is a Macro or Micro
That’s the long and short of macros vs micros, but there are some things we ingest that don’t fall neatly into those categories.
“Sometimes people say water is a macronutrient because we measure it in grams,” says Rizzo. “But it’s tricky because there are no set requirements for how much water you should have. Some people call it a macronutrient. I don’t know if it is one, but you could consider it one.”
Fiber is definitely a type of carbohydrate but with regard to insoluble fiber (found in grains and legumes and a lot of fruits), it passes through the body and isn’t really absorbed. It helps to give bulk to your stool and make pooping easier, so it’s definitely something you should eat, plus it helps slow digestion and minimize blood sugar spikes and decrease cholesterol absorption, the list goes on.(8)(9)(10)(11).
But because so much of it goes unabsorbed, it’s controversial as to whether or not the calories “count” from fiber.
“I’ve never really seen research on how many calories are absorbed in terms of fiber, and I feel like that’d be really difficult to figure out,” says Rizzo. “I don’t know if people subtract the calories in fiber, though they often subtract the carbs in fiber from their macros. But the bottom line is those calories still count.”
Alcohol contains 7 calories per gram and because it contains calories and it isn’t protein or fat and it’s not really a carb, strictly speaking. Although some macro trackers will call it a macro, it doesn’t give us energy the same way, it’s metabolized very differently, and it has more calories.
“I haven’t heard alcohol called a macro in school, but we tend to think of macronutrients in terms of the calories you’ll get for a gram,” says Rizzo.
Whether or not you consider it a macro, it is not an essential nutrient.
Omega-3 Fatty Acids
These are indeed types of fat so they are under the “fat” umbrella, but we’re including it here because Omega-3 content isn’t something you see on a standard nutrition label. Nutrition labels only say “fat,” and maybe how much of it is unsaturated or saturated. On rare occasions a nutrition label will mention how much is polyunsaturated fat, but Omega-3 is just one kind of polyunsaturated fat.
That’s a shame, because Omega-3s have close links to various benefits.
“Technically, Omega-3s are a fat, but that’s another one we’re not seeing on labels,” says Rizzo. “And there’s a ton of research that Omega-3s are beneficial for heart health and cognitive function. So there are things that are definitely left out in terms of macronutrients and micronutrients.”
[Related: The Best Omega-3 Supplements]
These are basically micronutrients that didn’t make the cut.
OK, it’s more complicated than that, but phytonutrients are found in plants and they include antioxidants, flavonoids, polyphenols, and various other chemicals that contribute to our overall health.
“There’s a million kinds of them,” says Rizzo. “There’s anthocyanin , flavonoids, all these different ones that are in all these fruits and vegetables, and they’re very hard to measure.”
Take broccoli, for example. It includes phytonutrients like,
- Indole-3-Carbinol, linked to hormonal health
- Isothiocyanates, linked to lower inflammation
- Glucosinolates, linked to antifungal and antimicrobial effects
But none of these are technically vitamins or minerals and they’re not considered essential for proper human functioning. They’re just very good for human functioning.
“Even if we did know how much of it you need in a day, there are no set standards there like with macronutrients and micronutrients,” says Rizzo.
They don’t provide calories, but they do provide benefits. Our digestive tract contains trillions of bacteria that help us to break down and digest food, and consuming more of them — found in supplements or fermented foods like yogurt, sauerkraut, and kimchi — may help to improve digestive health and decrease inflammation.
Macros and micros aren’t one hundred percent of your nutrition, but when it comes to maintaining your health, they’re hugely important and broadly considered the foundation of a healthy diet.
Macros are pretty much everything when it comes to weight loss and weight gain, and hitting your recommended intake of your micronutrients is linked to everything from better sleep to better immunity to better testosterone — better everything.
These are essential nutrients, and while there are non-essential nutrients like the phytonutrients mentioned earlier, so long as you continue to eat plenty of whole foods you’ll also be getting plenty of these healthful chemicals.
In other words, don’t just eat sugar, protein powder, butter, and multivitamins. Eat a lot of whole foods and a broader spectrum of macros, micros, fiber, phytonutrients, and more will follow.
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2. Slavin, J et al. Carbohydrates. Adv Nutr . 2014 Nov 14;5(6):760-1.
3. Liu, A et al. A Healthy Approach to Dietary Fats: Understanding the Science and Taking Action to Reduce Consumer Confusion. Nutr J . 2017 Aug 30;16(1):53.
4. Cao, Y et al. Magnesium Intake and Sleep Disorder Symptoms: Findings From the Jiangsu Nutrition Study of Chinese Adults at Five-Year Follow-Up. Nutrients . 2018 Sep 21;10(10):1354.
5. Schnabel R, et al. Selenium supplementation improves antioxidant capacity in vitro and in vivo in patients with coronary artery disease The Selenium Therapy in Coronary Artery disease Patients (SETCAP) Study. Am Heart J. 2008 Dec;156(6):1201.e1-11.
6. Puspitasari IM, et al. Updates on clinical studies of selenium supplementation in radiotherapy. Radiat Oncol. 2014 May 29;9:125.
7. Cai X, et al. Selenium Exposure and Cancer Risk: an Updated Meta-analysis and Meta-regression. Sci Rep. 2016 Jan 20;6:19213.
8. Fuller S, Beck E, Salman H, Tapsell, L. New horizons for the study of dietary fiber and health: A review. Plant Foods Hum Nutr. 2016; 71(1):1-12.
9. Lambeau KV, McRorie JW Jr. Fiber supplements and clinically proven health benefits: How to recognize and recommend an effective fiber therapy. J Am Assoc Nurse Pract. 2017;29:216–223. doi: 10.1002/2327-6924.12447.
10. Garcia AL, Otto B, Reich SC, et al. Arabinoxylan consumption decreases postprandial serum glucose, serum insulin and plasma total ghrelin response in subjects with impaired glucose tolerance. Eur J Clin Nutr. 2007;61:334–341.