What You Should Know About Strict No-Carb, No-Sugar Diets

Many diet trends have you severely restrict sugar and carbohydrates (looking at you, keto) or ditch them altogether. But because many beneficial foods — like fruits, veggies and whole grains — contain these nutrients, is a strict no-carb, no-sugar diet the way to go for weight loss or health?

If you're thinking of starting a no-carb, no-sugar diet, read on for what you need to know.

A no-carbs, no-sugar diet is much like what it sounds like: It's an eating plan that cuts carbohydrates and sugar from the menu. But it helps to know more about the nutrients before you decide to eliminate entire groups from your diet.

Carbohydrates are a macronutrient that provide your body with the energy it needs to function, according to the Cleveland Clinic. Sugars, starches and fiber are all types of carbs, and common sources of the nutrient include:

• Fruits and vegetables
• Legumes like beans, peas and lentils
• Whole grains like brown rice, oatmeal and whole-wheat bread
• Nuts and seeds
• Dairy products like milk

Fresh fruit and milk in particular are rich in naturally occurring sugars. And because these natural sugars are a beneficial part of balanced eating, diet plans that indicate "no sugar" typically mean cutting added sugar specifically.

Added sugar is sugar that has been added to a food during processing, per the Mayo Clinic. And while added sugar itself isn't necessarily bad for your health, the issue is that it's usually found in less-nutritious, processed foods like candy, baked goods or soda.

Common types of added sugar to check for on nutritional labels include:

• Cane juice and cane syrup
• Corn sweetener and high-fructose corn syrup
• Fruit juice concentrate and nectar
• Honey
• Malt
• Maple syrup
• Molasses
• Fructose, glucose, maltose and dextrose

Overall, it's difficult to completely cut carbs (including natural sugar) from your diet — in fact, it's generally not safe to go totally carb- and sugar-free, as you may not get the fuel or nutrients you need to function at your best, per the National Health Service (NHS).

The ketogenic diet is a popular low-carb and sugar diet. Keto involves a high-fat, moderate-protein, low-carbohydrate eating plan, and is often used for weight loss, according to the Harvard T.H. Chan School of Public Health. You can follow your own ketogenic diet, or choose a pre-made diet plan like that Atkins diet (which also contains plenty of its own health risks, per the Mayo Clinic).

The keto diet is largely known for its fat-burning abilities, per Harvard Health Publishing. Typically your cells use blood sugar (from carbs) to create energy. But in the absence of carbohydrates, your body breaks down body fat into ketones for energy.

Here's a typical breakdown of your daily nutrients on the keto diet:

• 70 to 80% fat
• 10 to 20% protein
• 5 to 10% carbohydrates

But does it work for weight loss? High-fat, low-carbohydrate diets may initially promote more weight loss than low-fat diets, according to a December 2018 study in the ‌Official Publication of the College of Family Physicians of Canada.‌ However, despite the diet's ability to use body fat for fuel, it seems to lose to its effect after about a year of dieting.

While it's still possible to get enough nutrients while on a low-carb diet, a no-carb diet is likely unsustainable and may leave you nutrient-deficient, per the NHS. For instance, vegetables are a source of carbohydrates, but also supply essential nutrients like fiber, antioxidants, vitamins and minerals.

The same goes for cutting out sugar: This approach is only healthy if you're eliminating added sugars. Nixing foods with natural sugars — like fruit and dairy — makes it extremely difficult to get the nutrients your body needs, according to the NHS.

Many people tend to overeat protein and poor-quality fats on a low-carb, no-sugar diet, so it's important to keep ingredients and portion sizes in mind. For instance, fill your plate with beneficial unsaturated fats rather than sources of trans or saturated fats (more on that later), according to Harvard Health Publishing.

Natural sources of carbs and sugar — like fruits, vegetables and whole grains — provide you with essential nutrients, so it may not always be best to cut these ingredients.

But if you do decide to try a no-carbs, no-sugar diet plan, here are some foods you may want to limit.

While you shouldn't cut out carbohydrate-rich produce entirely, you can limit these high-carb fruits and vegetables:

• Starchy vegetables like potatoes and sweet potatoes
• Bananas
• Grapes

Whole grains are also high in carbs, and may not be ideal for this type of diet. Here are some high-carb grains to limit:

• Amaranth
• Spelt
• Granola
• Quinoa
• Oatmeal
• Brown rice

If you're looking to cut back on carbohydrates and sugar, limiting processed foods is also a great place to start. Here are some foods to limit or avoid that are high in carbs and sugar:

• Soda
• Flavored beverages like coffee or juice
• Cereal
• Baked goods
• Syrups
• Jellies
• Candy

Following a no-carbs or sugar diet generally requires some planning and preparation, considering most processed convenience foods are high in both.

To help, here are some foods to prioritize in a no-sugar, no-carb diet.

Plants are a critical part of a balanced diet. Here are some low-sugar and lower-carb fruit and vegetable options to munch on:

• Coconut
• Avocado
• Tomatoes
• Rhubarb
• Lettuce
• Spinach
• Asparagus
• Cauliflower
• Broccoli
• Bell peppers
• Cabbage
• Green beans

Replace high-carbohydrate foods like bread, rice or potatoes with lower-carb options like riced cauliflower, according to the Mayo Clinic. Other alternatives include lettuce wraps or slices of eggplant.

Following a keto-style diet also entails raising your fat content. According to Harvard Health Publishing, limit trans and saturated fats and instead opt for foods that contain beneficial fats, like:

• Fish
• Olive oil
• Avocado
• Nuts and seeds

Instead of soft drinks or flavored beverages, which are typically high in carbohydrates and added sugar, sip fluids like water, plain herbal tea and black coffee to get variety and adequate hydration without the added carbs and sugars.