Low Carb-Style Eating

Judy Seybold, MS, RDN, LD, CLC
Chief Nutrition Officer

The low carb-style of eating was first popularized in the 1970s. Low carb diets limit carbohydrates and emphasize the intake of foods that are higher in both fat and protein content. Grains, starchy vegetables, and fruit are limited as well as some dairy products and legumes due to their higher carb content.

Low carb diets are often used for short-term weight loss but may also be used for blood glucose control in people with Type 2 diabetes and metabolic syndrome. Since the FDA doesn’t have a legal definition for low carb, you will find it defined differently by varying sources of information, which causes confusion.

How it Works

Carbohydrates are your body's preferred main source of fuel. They are broken down and absorbed into your bloodstream as glucose. Rising levels of glucose trigger insulin release, which helps get glucose into your body’s cells for energy. Excess glucose that isn’t used is usually stored in your liver, muscles, and other cells for later use or is converted to fat.

The idea behind the low carb diet is that decreasing carbs lowers insulin levels, which causes the body to burn stored fat for energy and ultimately leads to weight loss. Therefore, low carb dieters avoid foods that are rich in carbohydrates.

The number of carbohydrates people consume will vary depending on what they consider low carb. Restricting carbohydrates to less than 20 - 60g per day can result in ketosis, which is when your body breaks down the stored fat in the absence of glucose. Ketosis can cause nausea, headaches, mental and physical fatigue, and bad breath. Ketosis can happen in people with diabetes, but it is not very common in Type 2 diabetes. People with Type 1 diabetes want to avoid ketosis as it can be a life-threatening condition.

Carbohydrate-Rich Foods

• Grains
• Fruits
• Starchy vegetables
• Milk
• Legumes (beans, lentils, peas)

While non-starchy vegetables, nuts, and seeds do have some carbohydrates, but in considerably lower levels, making them acceptable to include in many low carb eating plans.

Lower-Carbohydrate Foods

• Eggs
• Fish
• Leafy green vegetables
• Meat
• Non-starchy vegetables, in general
• Nuts and seeds
• Oils
• Unsweetened dairy products

Low Carb Diet Pros

Carbohydrate restriction may benefit blood glucose control in those with Type 2 diabetes and metabolic syndrome. It can also lead to weight loss especially if carbohydrate intake was leading to an excess in calories or poor nutrition quality of foods. Limiting carbs may also limit sweets or highly refined carbs that don’t provide much nutritional benefit.

Low Carb Diet Cons

A lack of carbohydrates can cause headaches, weakness, muscle cramps, fatigue, constipation, and inability to perform athletic activities due to lack of stamina. There is a lack of long-term data to determine if there are long-term side effects of following this diet. Current evidence does not show a benefit over more traditional energy-restricted, nutritionally balanced diets both in terms of weight loss and weight maintenance.

Healthy Eating Tips

Dietary Guidelines for Americans recommend that carbohydrates make up 45 to 65 percent of your total daily calorie intake. That would be between 900-1300 calories on a 2000 calorie diet as opposed to getting about 20-60g of carbohydrate per day, which would be about 80 to 240 calories from carbohydrates.

If you want to lose weight or restrict certain carbs and the number of carbs or just prefer foods that have fewer carbs in them, then a low carb eating style may be for you. Include a variety of foods from all the food groups, even getting some whole grain products.

Plan out meals. Between meals, have go-to snacks ready such as hard-boiled eggs, carrots, a handful of nuts, cheese, and plain, unsweetened yogurt.

Finally, get clearance from your doctor before starting a low carb diet as it may be detrimental to your health if you have conditions like Type 1 diabetes. Your doctor can advise if there are any side effects that would merit a need to stop following this eating plan. A registered dietitian can also be helpful in planning balanced meals and snacks that include a variety of low carb food groups and help you meet your personalized health goals.

Shop Sifter for products that support a Low Carb-Style diet

Additional Resources

Diabetes & DKA (Ketoacidosis)
Harvard School of Public Health: Low-Carbohydrate Diets
Mayo Clinic: Low-carb diet: Can it help you lose weight?