I don’t think a day goes by that I don’t hear about the latest diet a person is following. It may be at a party, in the store, or my office. I watch how people pile their plates with burgers, ribs and salad and forgo the bun or potato salad at a BBQ. It’s quite clear that they’re avoiding carbs in their quest to lose weight, “lift brain fog” or “cure” their IBS (1).
Or there’s the other end of the spectrum -- people who don't seem to care about their health and take no issue with having seconds of cake, chips, or soda at those same functions. The reality is, being moderate is not sexy. We live in a society of black and white, good and evil, carbs or no carbs. But when it comes to our diet, moderation is actually vital.
A recent study published in The Lancet found that following either a low-carb OR high-carb diet increases the risk of death, while consuming healthy carbohydrates in moderation offers the most benefits to their health (2). Consuming less than 40% or higher that 70% of your calories from carbohydrates was linked with highest risk of death. Having moderate levels of carbohydrates (50-55% of calories from carbohydrates) offered the most benefit for longevity.
However, what constitutes a low-carb diet is not always the same from one person to the next.
Individuals that swapped carbohydrates with animal proteins and fats like beef, lamb, pork, chicken, and cheese had the most risk of mortality compared to people who consumed protein and fat from vegetables, nuts, and beans (plant-based foods).
Dr. Sara Seidelmann, a clinical research fellow in cardiovascular medicine from Brigham and Women’s Hospital in Boston states, "We need to look really carefully at what are the healthy compounds in diets that provide protection." Avoiding bread, pasta and potatoes is really trendy as a weight loss method. While a low-carb diet has been found to impart short-term weight loss and reduce cardiovascular risk, the long-term effects are proving to have more negative results, at least based on her study.
According to Seidelmann’s study, animal-based, low-carb diets may be linked with shorter overall lifespans and should not be encouraged. Registered dietitian Catherine Collins (with the UK’s National Health Service and who was not involved in the research) states, "On an 'average' 2,000 kcal-a-day intake, a diet of 30% calories from carbs equates to only 150g a day, with sugars (natural or 'added') contributing around 50g of that total. With a mere 100g of complex carb a day to play with, a lower intake of cereals, grains, and starchy vegetables is inevitable." Collins notes that avoiding healthful carbs limits fiber, which helps prevent constipation, reduces blood sugar and cholesterol levels. Government dietary guidelines in the UK advise at least 30% of our diet should come from starchy foods (3).
The study’s results will not be popular with people who believe fervently in a low-carb lifestyle. Seidelmann’s researchers studied over 15,000 people between the ages of 45-64 from diverse socioeconomic statuses over four regions of the U.S. Researchers used surveys to assess average calorie intake and percentage of calories from different food groups, defining the types of food and drink participants consumed, along with amounts and frequency. Subjects were followed for about 25 years, during which 6, 283 of them passed away.
The researchers evaluated how many extra years a moderate-carbohydrate diet could add at certain ages in addition to looking for the best range linked with reduced risk of early death. According to the study, from age 50, those who ate carbohydrates in moderation added an extra 33 years to their life expectancy compared to 29 years for those on a low-carb diet and 32 years for those consuming a high-carb diet.
Results of the study were included with seven other carbohydrate consumption studies of people in North America, Europe, and Asia, all of which found similar trends in longevity. There are some caveats, however. The investigators realize that these findings are observational and cannot prove cause and effect. They also note that a Western-style low-carbohydrate diet may include more animal-based proteins and fats, instead of vegetables, fruits, and grains (2, 4).
Despite these caveats, experts in the field believe that the results should not be discounted. “Current guidelines have been criticized by those who favor low-carb diets, largely based on short-term studies for weight loss or metabolic control in diabetes, but it is vital to consider long-term effects and to examine mortality, as this study did," said Nita Forouhi, Program Leader of the Nutritional Epidemiology program at the University of Cambridge. It’s not enough to concentrate on nutrients alone, but rather whether they come from animal or plant sources.
If carbohydrate intake is reduced in your diet and plant-based fats or proteins are added, then there can be health benefits. However, you may not reap those benefits if animal-based proteins replace carbohydrates. Unfortunately, many low-carb diets do not differentiate the type of food to be included in the plan.
While a person’s dietary choices will continue to vary based on culture, socioeconomic status, health, dietary beliefs and food preference, the best advice nutrition experts can give their clients is based on the 2015-2020 US Dietary Guidelines:
- Eat a plant-based diet including a variety of fruits, vegetables and legumes.
- Choose whole grains such as steel-cut oats, farro, quinoa, bulgur and whole wheat breads and cereals over refined starches such as white bread, white rice, cake, cookies and other pastries.
- Limit added sugars from sugary beverages, candy and desserts.
- Limit saturated and trans fats. Choose healthy fats such as avocados, nuts, seeds and vegetable-based oils.
- Include lean sources of protein such as fish, poultry and low-fat dairy products.
- Enjoy alcohol in moderation.
- Lead an active lifestyle.
By Lisa Andrews, MEd, RD, LD
- Seidelmann, S, Clagget, B, Cheng, S, Henglin, M, Shah, A, Steffen, L, Folsom, A, Rimm E, Willett, W, Solomon, S. Dietary carbohydrate intake and mortality: a prospective cohort study and meta-analysis. Published August 16, 2018, open access. The Lancet, Public Health.
Hiroshi Noto, Atsushi Goto, Tetsuro Tsujimoto, and Mitsuhiko Noda. Low-Carbohydrate Diets and All-Cause Mortality: A Systematic Review and Meta-Analysis of Observational Studies. PLoS One. 2013; 8(1): e55030. Published online 2013 Jan 25.
Stephanie Ronco has been editing in a professional capacity for the past 10 years. In addition to her work as an editor, Ronco has also served as a ghostwriter and writing tutor. A voracious reader, Ronco loves watching language evolve and change. When she’s not delving into her latest project, Ronco can be found teaching acting classes, performing in community theater, or sailing with her husband.