Low Carb Vs. High Carb Diets: Long-term Impacts

Health Writer

Carbohydrates are delicious. Muffins, donuts, pizza crust, fresh baked rolls, stir-fry rice, your favorite cereal, pancakes, waffles, ice cream cones, Chinese noodles, pastas, need we go on? Of course, fruits and vegetables are also carbohydrates, however, they’ve been relegated to a less important spot in most American diets. One of the most popular diet trends to lose weight and treat diabetes has been a low carb or very low carb diet.

Most of us are eating too many unhealthy carb-based foods. People who eat fruits, vegetables, and less processed grain products are probably on the right track except that these healthy foods also break down into simple sugars when digested. Too much sugar – even when sourced from less processed, simple foods - is too much sugar, and not good for our health.

Excess sugar gets stored as fat, and constantly bombarding our body with sugar tests our pancreas and can ultimately result in impaired insulin function and type 2 diabetes. You can also gain weight if you eat too many (healthy) carbs – especially grain carbs. Processed carbs also tend to have significant amounts of added sugars and the body stores excess sugar calories as fat.

Long-term effects on mortality

Studies have confirmed that a short-term low carb diet can help with relatively rapid weight loss. People also tend to experience improved metabolic health on these low carb diets, at least in the beginning. The problem is that when we cut carbs, we typically replace them with animal protein and fatty foods. A 2018 study published in The Lancet Public Health found that the long-term effects of carb restriction may include shortened life expectancy by four years, if animal protein and fat consumption increase to compensate for the lack of carbs.

When the term 'low carb diet' is used, that typically means that 40 percent or less of the diet is derived from carbs. 'High carb diet' means that 70 percent or more of the diet comes from carbs. Dr. Dean Ornish, a well-known cardiologist, pioneered the concept of a plant-based diet approach that focuses on fruits, vegetables, and whole grains with legumes, soy, egg whites, and non-fat dairy products as the main sources of protein.

The diet skewed significantly high in carbs, but severely restricted refined carbs like sugar, white flour, white rice, white pastas, and concentrated sweeteners. The diet also controlled fats (10 percent of total daily calories), only allowing tiny amounts of fish oil, flaxseed oil, nuts, and seeds. Patients able to sustain the diet long-term (it’s quite challenging) experienced dramatic improvements in heart disease and diabetes symptoms.

Implementing plant-based foods

What counts most is the type of fat, protein, and carbs you choose to eat. Secondarily, it’s important to consider how much of each type of food you consume because it will affect weight gain and other health parameters. The sweet spot seems to be a diet that is comprised of 50 to 55 percent carbs (moderate carb diet), with the balance of calories sourced from plant-based proteins and fats.

The Lancet study was a large study involving over 15,000 adults in four U.S. communities. The study followed these individuals periodically for 25 years. The research suggests that if you do go low carb, it’s crucial to replace the carbs with plant-based proteins (beans, seeds, legumes, nuts, soy) and plant-based fats (olive oil, nut oils, canola oil, soybean oil) to avoid a shortened life expectancy. Diets rich in plant-based foods in general, promote healthy aging and longevity over the long-term.

If you want to choose low carb, go ahead, but do it the right way by choosing plant-based proteins (and fish) and small amounts of healthy fats as your major carb replacements. If you can’t sustain a diet without animal-based foods, then select poultry, non-fat dairy products and egg whites, and plant-based fats. Most importantly, follow a healthy low carb diet for the short term and then carefully reintroduce additional portions of healthy grains, fruits and vegetables, fish, and fats like olive oil.

See more helpful articles:

Best Fruit Choices if You Have Diabetes

Low Carb Diets and Gender Differences

Why Are Companies Still Adding So Much Sugar to Foods?