Low Carb and Weight Loss: Do Carbs Make You Fat?

First off, no, this is not a blog post about the Atkins diet, I just wanted to put a picture up that everyone associates with low-carb diets (Sorry, my creativity is lacking this week). Ok, now that I cleared that up lets begin!

Last week I opened the discussion of Low-Carb (LC) Diets and how they have been linked to disease prevention and weight loss.   I also briefly went over how LC diets have been effective in preventing/treating diseases such as type 2 diabetes, metabolic syndrome, heart disease, and epilepsy.  This week I want to tackle the mystery surrounding LC diets and weight loss and how they compare to the standard low-fat high carbohydrate (LFHC) diet prescribed by the American Dietetics Association.

For years we have been told that LFHC diets rich in whole grains are the best for weight loss.  We had it pounded in our heads that we should eat oatmeal by the bucket and whole wheat bread by the loaf while keeping our fat intake as low as possible and our meat consumption as moderate as possible.  But then we saw some radical ideas come from left field. Low-carb diets like Atkins boomed, south beach went viral, and the Zone diet dominated the fitness scene. Both “diet” approaches had credible backing too, I mean the FDA endorsed LFHC with plenty of whole grains (I wonder if government subsistence had anything to do with that…..) and Dr. Barry Spears preached “Zone, Zone, Zone”.  So what’s the deal? Which camp is right? Which camp is wrong? It has to be one or the other doesn’t it?

I am going to present the data and let you decide and then I will give you my personal take on the issue.

The Data

Let’s get a little nerdy and begin with what I consider a fairly important study. A study titled “Weight loss with a low-carbohydrate, Mediterranean, or low-fat diet” published in the New England Journal of Medicine examined the effect of effect of three different diets: low-fat restricted-calorie; Mediterranean, restricted-calorie; or low-carbohydrate, non-restricted-calorie in a randomized clinical trial (the mother of all study designs).

Before we dive into what these researchers found, lets step back and think for a minute. If the FDA recommendations were correct the low-fat diet would promote the most weight-loss, and if the calories-in vs. calories-out hypothesis told the whole story we would make the same assumption, correct?

Here is what they actually found. among the participants who completed the intervention.

Low-Fat Mediterranean-diet Low-Carb
Avg. Weight Loss 3.3 kg (7.3 lbs) 4.6 kg (10.21 lbs) 5.5 kg (12.21 lbs)  

The results of this study fly in the face of most conventional wisdom. The FDA lauded low-fat diet showed the lowest weight loss, even though it was a restricted-calorie diet while the LC diet displayed the highest average weight loss despite being non-calorie-restricted.  They also examined blood work of all the participants and found improved blood-lipid profiles and glycemic control among the LC and Mediterranean diets. Ultimately the researchers drew the following conclusion,

“ Mediterranean and low-carbohydrate diets may be effective alternatives to low-fat diets. The more favorable effects on lipids (with the low-carbohydrate diet) and on glycemic control (with the Mediterranean diet) suggest that personal preferences and metabolic considerations might inform individualized tailoring of dietary interventions”(1).

So what? It is just one study, I mean we see studies all the time that say something only for it to be proven false later.

Excellent point! Unfortunately for you “Pastatarians” or “Bageltarians” there is more than research to substantiate these findings.

A randomized trial comparing a very LC diet and a calorie-restricted LF diet with weight loss and CVD risk factors in healthy women found that a very low carbohydrate diet is more effective than a low fat diet for weight loss and, over 6 months, is not associated with deleterious effects on important cardiovascular risk factors in healthy women (2).

Yet another long-term randomized study examined the same thing but in a different sample of people and found that participants on a low-carbohydrate diet had more favorable overall outcomes at 1 year than did those on a conventional diet. Weight loss was similar between groups, but effects on atherogenic dyslipidemia and glycemic control were still more favorable with a low-carbohydrate diet after adjustment for differences in weight loss (3).

Now I could continue and cite all of the 20+ research studies I read last night but that would be repetitive and fairly boring after a while. So the last research article I with leave you with is a meta-analysis published in the Archives of Internal Medicine which made the following conclusion

”Low-carbohydrate, non–energy-restricted diets appear to be at least as effective as low-fat, energy restricted diets in inducing weight loss for up to 1 year.  However, potential favorable changes in triglyceride and high density lipoprotein cholesterol values should be weighed against potential unfavorable changes in low-density lipoprotein cholesterol values when low-carbohydrate diets to induce weight loss are considered” (4).


I try to be extremely careful when I draw conclusions from research as the studies are usually very specific, and this is no exception. Almost all of these studies are looking at weight-loss and CVD disease, which is something we ought to keep in mind. From the research studies, my own beliefs, and experiences, here would be the conclusions I would draw.

1) LC diets appear to be more effective than LFHC diets in regard to short-term weight loss

2) LC diets also appear to be more beneficial in regards to plasma lipids and glycemic control.

3) There are no well-known negative side effects of a LC diet.

Here are my closing thoughts.  In general, I am “agnostic” in my views on macronutrient content when it comes to the optimal diet.  I do not believe carbs are evil, in fact, I myself have switched from a LC to a moderate carb diet as I have been lifting heavier, doing more high-intensity exercise and am currently attempting to get a little bigger and stronger (what male in their 20’s is not?). I do not  prescribe to a specific camp (i.e. low-carb vs high-carb). However, that being said I do believe that a LC approach to a diet is the most effective approach if weight loss is your goal, you are not extremely active and looking to prevent weight gain, or are looking to help control type 2 DM, metabolic syndrome, or other diseases that have metabolic underpinnings and may be beneficial in preventing certain degenerative diseases.

Next week we are going to get into the fun side of this stuff, the meat and bones. I am going to get a little nerdy and explain why LC diets help with disease and are more effective at weight loss. You all are in for a real nutrition/physiology lesson and adventure next week!

Also, tune in Friday for a Paleo-diet focused podcast, its gonna be epic!!

1. Shai I, Schwarzfuchs D, Henkin Y, et al. Weight Loss with a Low-Carbohydrate, Mediterranean, or Low-Fat Diet. N Engl J Med. 2008;359(3):229–241.

2. Brehm BJ, Seeley RJ, Daniels SR, D’Alessio DA. A Randomized Trial Comparing a Very Low Carbohydrate Diet and a Calorie-Restricted Low Fat Diet on Body Weight and Cardiovascular Risk Factors in Healthy Women. Journal of Clinical Endocrinology & Metabolism. 2003;88(4):1617–1623.

3. Stern L, Iqbal N, Seshardi P, et al. The Effects of Low-Carbohydrate versus Conventional Weight Loss Diets in Severely Obese Adults: One-Year Follow-up of a Randomized Trial. Ann Intern Med. 18 May 2004;140(10):778-785

4. Nordmann AJ, Nordmann A, Briel M, et al. Effects of Low-Carbohydrate vs Low-Fat Diets on Weight Loss and Cardiovascular Risk Factors: A Meta-analysis of Randomized Controlled Trials. Arch Intern Med. 2006;166(3):285-293.


Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google+ photo

You are commenting using your Google+ account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )


Connecting to %s

Examine.com - A Look into the Surprising Elements of Supplements

An Evolutionary Approach to Health, Nutrition, and Fitness

Evolutionary Health Perspective

An Evolutionary Approach to Health, Nutrition, and Fitness

The Daily Lipid

An Evolutionary Approach to Health, Nutrition, and Fitness

Whole Health Source

An Evolutionary Approach to Health, Nutrition, and Fitness

Chris Kresser

Let's take back your health - Starting Now.

Catalyst Athletics: Olympic Weightlifting

An Evolutionary Approach to Health, Nutrition, and Fitness

PaleOMG – Paleo Recipes

An Evolutionary Approach to Health, Nutrition, and Fitness


An Evolutionary Approach to Health, Nutrition, and Fitness

Evolutionary Health Perspective

An Evolutionary Approach to Health, Nutrition, and Fitness

%d bloggers like this: