Which Diet Is Best? Plant-Based, Low-Fat vs. Animal-Based, Low-Carb

Typically, a diet high in carbohydrates was thought to make a person hungry all the time, while a diet high in fat would lead to weight gain.

Well, a new study, led by researchers at the National Institute of Diabetes and Digestive and Kidney Diseases and conducted by the NIH Clinical Center’s Metabolic Clinical Research Unit, compared two popular diets:

After comparing the outcome of the two diets for calorie intake, hormone levels and body weight, the researchers found that the results revealed neither of these assumptions to be the case.

What was the study? For four continuous weeks, 20 adult participants (11 men and 9 women) were given either a plant-based, low-fat diet or an animal-based, low-carb eating plan for two weeks. Then they immediately switched to the other eating plan for another two weeks.

Participants received three meals a day plus snacks and could eat as much as they wanted. Both diets were considered minimally processed and both included equal amounts of non-starchy vegetables such as beets, cauliflower and mushrooms.

The researchers concluded that the plant-based, low-fat diet led to a lower intake of calories – about 550 to 700 fewer calories per day. The animal-based, low-carb diet produced more steady insulin and glucose levels. All participants lost weight on both diets; however, the plant-based, low-fat group lost more body fat.

In the study, a typical dinner might include a baked sweet potato, chickpeas, broccoli and oranges. Overall, the diet contained 10.3% fat, 75.2% carbohydrates and around 14% protein; the percentages are based on total calories eaten.

In the study, a typical dinner might include beef stir-fry with cauliflower rice. Overall, this diet contained 75.8% fat, 10% carbohydrates and also around 14% protein.

Plant-based, also known as plant-forward, diets have become very popular over the last couple of years. Research has associated a diet rich in plant foods, such as whole grains, fruits, vegetable and nuts, with a lower risk of cardiovascular disease. Including more plants in your diet has also been shown in scientific studies to help decrease the risk of certain cancers.

Low-carb diets have been popular for years. The keto diet is an example of a low-carb diet that’s enjoyed a lot of popularity in recent years. There is some research to support that a low-carb diet may help improve blood sugar control and in some instances be a successful treatment for Type 2 diabetes. There have also been some studies that reveal a low-carb diet may help reduce the risk of cardiovascular disease.

An animal-based diet that is high in saturated fat may lead to an increase risk in heart disease. According to a study published in 2017, researchers found replacing saturated fat with mono or poly-unsaturated fats as well as adding high-fiber carbohydrates – such as legumes, oats, barley and quinoa – led to a reduction in heart disease.

As the new study above revealed, there may be pros to both diets for lowering calorie intake. However, this study by the NIH was only four weeks long, and included only a small group of participants, making it rather hard to draw a conclusion about the long-term effects.

That’s the problem with many studies looking at diet: The length of time is too short, or there are not enough participants. Also, in some studies, there are too many other factors thay many not be controlled for – such as underlying health issues or physical activity. Keep in mind too that in the NIH study, all meals were prepared and given in a lab, not planned, shopped and cooked by the participant in a real-life situation.

I think the authors of this study said it best: “The best answer to the question of which ‘diet’ is best for weight loss is the one that an individual will be able to stick to over the long haul.”

Agreed. However, I’d also like to add that not all diets are about weight loss, but rather health. And I hope we can all agree that a diet rich in whole grains, fruits, veggies, legumes, nuts and seeds should be a part of all of our diets. Final answer.