“Unless you’re eating chicken and steak all day, it’s nearly impossible to go on a no-carb diet,” says nutritionist Karen Ansel, M.S., R.D.N., author of Healing Superfoods for Anti-Aging. “Not only are carbs in foods like bread, pasta and fruit, they’re also in foods like nuts, beans, lettuce and broccoli.” Fruits and vegetables are the best carbs for you, because they contain the most vitamins, minerals, and fibre. So when we talk about going low-carb, we’re talking about cutting refined sugars, refined grains like pasta, whole grains and starches like brown rice and quinoa. Whole grains increase your blood sugar and insulin levels at a healthy (but not excessive rate) and regulate your microbiome.
“By eating too few carbs, you’re getting less prebiotics and total fibre,” says Jackie Newgent, RDN, CDN. “Most guys likely need more not less prebiotics – which are the fuel for beneficial probiotics in the gut.”
“To go low-carb the right way, realise that you are going to need some carbs for energy, nutrients and fibre, so get them from nutrient-packed lower-carb sources like vegetables, nuts and seeds,” Ansel says. “And keep in mind that the very lowest you should ever go is 20 grams of carbs a day. Less than that will cause your body to go into ketosis which can make you feel nauseous, weak and generally lousy.”
How lousy is it, you ask? Here are some of the uglier potential side effects of going low-carb:
“In addition to giving your muscles the energy they need to power through a workout, your brain runs on carbs too,” Ansel says. “In fact, it burns through close to 500 calories worth of carbs a day, so if you’re cutting carbs to the bare bones you’re going to feel it, and it’s not going to be pretty.”
“Your brain relies on carbohydrates for energy,” says Tanya Zuckerbrot, MS, RD. “Without them, your brain power will suffer and that midday crash might hit you hard. You might find it hard to focus throughout the day.”
Newgent stresses the importance of eating carbs during active times of the day to fuel working muscles, like pre- or post-workout, for example. In fact, you need more carbs the longer you work out, because increased glycogen in the muscles has been correlated to better performance in strength and endurance exercises.
2. MOOD SWINGS AND IRRITABILITY
“Without enough carbohydrates, your blood sugar will drop, leaving you feeling moody,” Zuckerbrot explains.
“Because carbohydrates are critical for production of the mood balancing brain chemical serotonin, you’re likely to be irritable as well,” Ansel adds.
“Carbs are the only food source that contains fibre,” says Keri Gans, MS, RDN, CDN and author of The Small Change Diet. “Fiber helps to control blood glucose levels, may help lower cholesterol, and promotes bowel regularity.”
By skipping fruits, vegetables, and whole grains, you’ll likely develop an ugly case of constipation. To avoid this, be sure to eat high fibre fruits like raspberries, blackberries, blueberries, apples and pears. Legumes like beans, peas and lentils, whole grains, and winter squashes such as butternut squash and spaghetti squash are also good options.
4. BAD BREATH
“When your diet is lacking in carbs, your body starts burning fat as fuel, producing ketones,” Zuckerbrot says. “Acetone, one of the ketones, causes your breath to smell fruity [and sour].” In fact, one study found that breath acetone is a good indicator of whether you’re eating too few carbohydrates.
So what’s the right way to go carb-free? “There is no right way. Carbs are a necessity and should not be eliminated from the diet,” Gans says. But if you’re looking to drop a few inches along your waistline, skip the refined sugars and simple starches. In other words, put down the doughnut and grab an apple.
This article originally appeared on Men’s Health US.