We have become a diet nation looking for the best way to shed pounds at any cost. According to the latest National Health and Nutrition Examination Survey data, the prevalence of obesity in the U.S. was 41.9% between 2017 and March 2020. Breaking it down further, 30.7% of U.S. adults are overweight, 42.4% have obesity and 9.2% have severe obesity.
Excess weight heavily increases the risk for chronic diseases such as Type 2 diabetes, heart disease, stroke and certain forms of cancer. Although the U.S. Department of Agriculture offers recommendations on the amount of fat verses carbohydrates in a healthy diet, there has still been much debate on whether a low-carbohydrate diet is better for weight loss verses a low-fat diet. Below you will find out more about each type of diet and which the research shows is more effective for weight loss.
What Is a Low-Carb Diet?
The 2020-2025 dietary guidelines for Americans recommend between 45% and 65% of your total daily calories come from carbohydrates. On a 2,000 calorie average American diet, this means consuming between 900 and 1,300 calories — or 225 to 325 grams — from carbohydrates..
Carbohydrates are an essential nutrient and can be found in numerous food groups, including milk and dairy, fruit, grains, starchy vegetables like potatoes and in smaller amounts in low-carb vegetables (like spinach and broccoli). Fiber-rich foods like beans, lentils and whole grains also fall into the category of carbs.
You can also find sources of carbs from added sugars found in sugar-sweetened beverages, which are the top source of carbohydrates for Americans, according to the dietary guidelines. Cakes, cookies, candy and other added sugar sources like granulated sugar are also sources of carbs. Some believe that having a diet high in carbs can lead to large swings in the body’s insulin levels, which may lead to increased hunger and consuming more calories.
Some low-carb diets, like keto, cut back significantly on carbs, limiting carbs to no more than 50 grams per day. These small amounts typically come from low-carb vegetables (like spinach and carrots), avocados and lower sugar fruit like apples and berries.
The decrease in carbs comes with the increase of calories from fats and protein. However, is it really healthy to advocate high amounts of fat — including sources of saturated fat — and moderate protein in the diet? Saturated fat has been linked to an increased risk of heart disease, while higher amounts of protein can lead to kidney issues.
[SEE: 12 Fruits You Can Eat on a Low-Carb Diet Plan.]
Can You Lose Weight on a Low-Carb Diet?
Besides the keto diet, there are various other low-carbohydrate diets, including Atkins, Dukan, GAPS, Herbalife, MIND, OPTAVIA and paleo. Many folks have lost weight on these diets. But what does the science show in terms of effectiveness.?
A 2014 published review study found that low-carbohydrate diets compared to low-fat diets decreased body weight and also improved cardiovascular risk factors. The research does show that you can lose weight on a low-carbohydrate diet, however, that doesn’t necessarily mean that you can’t lose weight on other diets too.
A randomized trial published in the New England Journal of Medicine compared weight loss on people assigned to a low-carbohydrate, high-protein, high-fat diet or a low-calorie, high-carbohydrate, low-fat diet. Researchers found that the low-carbohydrate diet resulted in a greater weight loss compared to the conventional diet for the first six months, but the difference was not significant at one year. The low-carbohydrate diet was also associated with greater improvement in some risk factors for coronary heart disease.
Another 2009 published randomized control study compared different weight loss strategies over two years, including a low-carb diet. The researchers found that healthy diets that varied the proportions of different macronutrients (carbohydrates, protein and fats) worked similarly and equally well in the long term, and that one diet wasn’t quicker than another in terms of weight loss.
[READ: Surprisingly High-Fat Foods.]
What Is a Low-Fat Diet?
Low-fat diets are not meant to be a zero fat diet and promote the consumption of healthy fats, including avocado, nuts, olive oil and fatty fish. Examples of low-fat diets include intermittent fasting, Ornish diet, Plantstrong diet, Pritikin diet and sirtfood diet. Typical low-fat diets limit fat intake to 20% to 30% of total calories from fat.
The federal dietary guidelines recommend consuming 20% to 35% of total calories from fat. On a 2,000 calorie diet this means consuming between 400 to 700 calories from fat. It also limits sources of saturated fat to no more than 10% of total calories or a maximum of 200 calories. As previously mentioned, the dietary guidelines are in place to help prevent chronic diseases like heart disease and also for those with one or more chronic diseases.
The American Heart Association has also set forth recommendations for weight management, which include avoiding too many calories and regular physical activity. It recommends total fat of 30% or less of total calories, or 600 calories based on a 2,000 calorie diet. This makes sense as fat provides nine calories per gram compared to carbohydrates and protein with 4 calories per gram each. The American Heart Association also recommends no more than 10% of total calories from saturated fat. Further, due to the increased evidence of cardiovascular benefits of fish (specifically fatty fish), two serving per week is also recommended.
High fat foods may lead to calorie overconsumption as they contain more calories per bite, and some high fat foods make you feel less satisfied after a meal.
Can You Lose Weight on a Low Fat Diet?
Low fat diets can certainly lead to weight loss, especially when calories are kept within reasonable limits. Researchers from the National Institutes of Health’s National Institute of Diabetes and Digestive Kidney Disease looked at people who followed a plant-based, low-fat diet with a high amount of carbohydrates or an animal-based, low-carb diet that was high in fat. Both diets had the same amount of calories and protein. Each person was given one diet to follow for two weeks, and then the same people followed the opposite diet for two weeks. The results showed that folks lost weight on both diets.
The low-fat diet led to a significant loss of body fat compared to the low-carbohydrate diet. The low-fat diet did result in higher blood glucose and insulin levels compared to the low-carbohydrate diet.
Low Carb vs. Low Fat
Research shows that you can lose weight on a low-carbohydrate and a low-fat diet. However, each diet has its advantages and disadvantages. For example, a low-fat diet can help decrease body fat while a low-carbohydrate diet has better glucose and insulin control.
In addition, when on a low-carbohydrate diet, it is essential to consume adequate amounts of whole grains and sources of fiber (like beans, fruits and vegetables). It’s recommended to get between 25 to 40 grams per day of fiber, and most Americans consume less than half that amount.
Restricting carbohydrates, means that carbohydrates should be selected carefully to be nutrient-dense verses choosing non-nutritive choices like donuts, cookies and soda. The same goes for a low-fat diet, where more carbohydrates are selected. In both cases, healthy carbohydrates should be selected in order for the individual to be able to take in all their nutrients.
Further, low-carbohydrate diets should focus on getting healthy sources of fat such as avocados, olive oil, nuts and seeds verses sources that are high in saturated fat. Due to the increase in trimming practices over the last half century, there are also many lean meat options available from beef, pork and lamb. As such, a low-carbohydrate diet is possible focusing on healthier fat from both animal and plant sources.
Which Is the Healthier Diet: Low Carb or Low Fat?
Both options can be healthy, but both can also be unhealthy. A study published in the Journal of the American Medical Association found that both diets had no significant difference in the rate of weight loss over 12 months. In addition, insulin secretion for each person, which was measured at the beginning of the study, was not associated with the dietary effects on weight loss. As such, there really was no difference in the two diets for weight loss.
Regardless of which diet you choose, you still want to take in all the nutrients your body needs in order to stay healthy and also keep calories under control. This means there should be no elimination of food groups, and a promotion of foods like whole grains and high-fiber foods on both a low-carbohydrate and low-fat diet. For both diets, healthy and lean sources of fat should be selected in order to keep in line with the guidelines of no more than 10% of total calories from saturated fat. Added sugars and sodium are also two nutrients Americans tend to over consume, and those should also be kept at no more than 10% of total calories and at 2,300 mg, respectively.
[READ: Are Low-Fat Low-Carb Diets Compatible?]
Can You Do a Low-Carb and a Low-Fat Diet at the Same Time?
The short answer is no. When you start cutting both carbohydrates and fat at the same time, it automatically means you’ll be getting many more calories from protein. High-protein diets can increase the risk for kidney damage, plus you’ll be cutting back too much from your other macronutrients that a sound diet is not possible and you won’t be able to meet all your nutrient needs.
Further, if you choose a low-fat diet while going higher on protein, you’ll also be restricted on beneficial plant-based carbohydrate and fiber sources, including beans, lentils, nuts and seeds. Ultimately, you’ll be left mainly eating a diet with lean meat with little variety and other healthy foods on your plate.
Both carbs and fat are two macronutrients your body needs to stay healthy. However, recommended range of intake for both nutrients can vary based on individual needs and preference, and both diets have been shown to be equally effective in short-term weight loss. As such, you can play with the levels of carbohydrates and fat (making one slightly higher and one slightly lower) in the diet and still be able to consume all the nutrients needed for a sound diet.
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Is a Low-Carbohydrate Diet Better for Weight Loss Compared to a Low-Fat Diet? originally appeared on usnews.com
