Low-Carb vs Low-Fat: The Battle Continues…

Forest Plot Weight Loss Study

A new meta-analysis published in PLos One sheds light on which diet is superior for weight loss. Low-fat or low-carb, which is the way to go? Image Courtesy PLoS One.[1]

Yankees and Red Sox. Cowboys and Indians. Buckeyes and Wolverines. The fabric of America is woven together through bitter rivalries that define not only decades, but entire periods of our rather brief history.

However, all of these pale in comparison to the great debate that has dominated the news for the past 25 years: Low-Fat versus Low-Carb – which diet is truly superior when it comes to weight loss.

The 90s were dominated by all things low fat. Everything from cookies to candy to chocolate cake was made of simple sugars and Frankenstein fillers all in an effort to avoid the intake of dietary fat at all costs. Because the thinking was, eating fat makes you fat.

The new millennium ushered in a new era of diet fat, the low-carb diet. Founded by carbo phobes, Atkins addicts, and Paleo people, all things high protein and high fat were in vogue and the humble carb was banished to the darkest corners of the closet. The mere thought of a piece of bread after 6pm would automatically lead to fat gain.

Both sides of the great debate have their legions of loyal followers and each uses a select few handpicked studies to back their dietary philosophies that “prove” their way of eating is superior to all others.

In the latest spin around the dietary carousel from hell, a new meta-analysis of several past studies may just give credence to one side that ultimately settles which is truly superior Low-Carb or Low-Fat.

The Meta-Analysis Study

Prisma Diagram Diet Study

Of all the 490 studies comparing low-fat to low-carb diets, only 17 met the design criteria of the meta-analysis. Image courtesy PLoS One.[1]

Rather than begin an entirely new study from scratch with fresh test subjects, a group of researchers performed a systematic literature review via PubMed of 17 randomized clinical trials. The panel’s focus was to compare the effects of low carbohydrate versus low fats diet on weight and atherosclerotic cardiovascular disease (ASCVD) risk in overweight and obese patients.

Only 17 of 490 studies were good enough to use

The group started with a total of 490 studies and based on their selection criteria, only 17 were found to meet the requirements. All of the randomized controlled trials lasted ≥8 weeks, including follow up, comparing low carbohydrate (≤120gm carbohydrates/day) and low fat diet (≤30% energy from fat/day).

In total, 1,797 patients over 18 years old were reviewed across the 17 studies.

When reviewing impact on cholesterol levels, low-carb diets significantly improved beneficial changes in HDL (“good”) cholesterol and triglycerides, while low-fat was more effective in altering LDL (“bad”) cholesterol and total cholesterol.

Weight Loss Winner: Low-Carb Diets!

Comparing the diets in terms of weight loss, low-carb diets showed statistically greater reduction that low-fat diets. Overall, seven of the 17 included trials favored the low-carb diet while none favored the low-fat option.


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The meta-analysis comparing Low-Carb diets to Low-Fat diets found that each diet was associated with significant weight loss and reduction in predicted risk of ASCVD (atherosclerotic cardiovascular disease). However, low-carb diets were associated with “a numerically modest but statistically significantly greater improvement in weight loss and reduction in predicted ASCVD risk.”

While the differences in weight loss between the two diets appears modest, the authors suggest that a “mega-trial” involving thousands of studies be performed to see the effect of low-carb vs low-fat on more “intermediate” risk markers and then judge whether changes would lead to long term reductions in CVD risk.

Furthermore, the researchers suggest revamping current dietary recommendations that favor low-calorie, low-fat diets in favor of low-carbohydrate diets, especially in the cases of obesity.

Our Take

Seems like a slam dunk for the low-carb diet crowd doesn’t it?

Not so fast…


As discussed in our newly-updated best fat burner buyer’s guide… this one is for serious dieters only!

The study was supported (i.e. funded) by Atkins Nutritionals, a decidedly pro-low carb diet pundit. While the study claims Atkins had no role in study design, data collection and analysis, or the decision to publish the results, you can’t help but wonder how the end result conveniently favors those who backed the study. or preparation of the manuscript.

Were all of those 473 studies not chosen discluded for legitimate reasons?

In our opinion, this doesn’t definitively settle the great debate one way or another. It’s merely another shot fired in the war on weight loss and depending on which side of the battlefield you stand on, you may want to take cover.

Ultimately, weight loss comes down to a controlled diet and a solid fitness plan. Both approaches clearly work, it just matters which one you can stick to as a lifestyle. If you’re a carb fiend but can still drop weight while enjoying your carbs, then the low-fat approach works for you. If you try low-carb and end up binging every weekend, thus ruining your diet, you’ll never succeed in weight loss and end up miserable.

Don’t be married to one nutritional philosophy for the rest of your life. Enjoy things in moderation, keep overall calories in check, and hit both the weights and cardio and you’ll see the scale start to tip the right way with diligence and hard work.

About the Author: Mike Roberto

Mike Roberto

Mike Roberto is a research scientist and water sports athlete who founded PricePlow. He is an n=1 diet experimenter with extensive experience in supplementation and dietary modification, whose personal expertise stems from several experiments done on himself while sharing lab tests.

Mike's goal is to bridge the gap between nutritional research scientists and non-academics who seek to better their health in a system that has catastrophically failed the public.

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  1. Sackner-Bernstein J, Kanter D, Kaul S (2015) Dietary Intervention for Overweight and Obese Adults: Comparison of Low-Carbohydrate and Low-Fat Diets. A Meta-Analysis. PLoS ONE 10(10): e0139817. doi:10.1371/journal.pone.0139817

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