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Saturday
Jul072012

Low-Carb vs. Low-Fat — What Does Research Show?


The use of a reduced-carbohydrate diet is surrounded in myth and misunderstanding. Though carbohydrate reduction has been used in practice for more than a couple centuries, only over the past 50 to 60 years has it come under attack as being ineffective or even unhealthy. From personal experience, I know that even many supposed experts in health and fitness perpetuate false information about “going low-carb.”

To satisfy some curiosity as well as to put together a resource I can refer back to when needed, I summarized 14 random, controlled diet trials that compared reduced-carbohydrate diets to low-fat diets. You can download the PDF of the table I created by clicking on the image below. If you'd prefer to just read about the highlights, read on below.

 

What is special about these studies? As mentioned, they’re random, controlled trials. This means different groups were assigned different diets and resources to help them adhere to the recommended nutrition plan. Of course, there is human error and, in most cases, study participants had freedom to veer off their expected plan. However, when you take such a large number of studies and understand the consistent results they deliver, you see some very consistent effects of lowering carbohydrate intake compared to standard “heart-healthy” low-fat recommendations.

If you tend to keep an eye on media headlines, keep in mind that most studies that make the news are observational studies. They look at a large population and see what trends exist. For example, a 25-year study from Sweden recently made headlines such as “Time to Retire the Low-Carb Diet Fad.” If you just read the headline, you got the impression low-carb doesn’t work, and the impression that it is just a fad (that’s been around for a couple hundred years). As is often the case, this study was observational. I’ll review the study and share the facts surrounding it at some point, but if a friends tells you about it, don’t worry about it.

Are reduced-carbohydrate diets effective for weight loss?

Let’s face it. Obesity is an enormous problem. The population of most of the world, especially the Western world, is fat. Take a look around at the mall, the airport or your state fair the next time you have the chance. If there is a better solution to help get peoples’ bodies back to healthy levels of body fat than carbohydrate restriction, research hasn’t shown it yet. In fact, when you look at the results of the lower-carb diets, even when people are free to eat as much as they’d like, they are far superior in terms of weight loss to calorie-controlled, low-fat diets.

If you were to read through many of the low-carb studies, you’d see the study participants often do not adhere to the exact levels of carbohydrate intake they’re supposed to. However, it’s still much lower than the low-fat comparison group, which is closer to the Standard American Diet. In most studies, weight loss and fat mass loss are close to double that of the results from low-fat diets. Again, in most studies, participants are instructed to keep carbohydrate to a maximum amount, often 20 to 50 grams to start. They’re then told they can eat as much food as they like, as long as they don’t exceed the 20 to 50 grams of carbohydrate.

The comparison group, the low-fat group, is often given an exact amount of calories they’re allowed each day. The calorie level is intended to force them into a calorie deficit to ensure weight loss.

Think about it. Which is more appealing? To follow a calorie-controlled diet where foods should be weighed and measured each day to ensure you don’t overeat, or follow a diet where you can eat as much as you’d like of most foods, other than starches, and get the added bonus of greater weight loss? In the research, those following the lower-carb diets often eat fewer calories than those following the low-fat, calorie-controlled diets, but it’s by choice. No weighing or measuring is required. They just eat until they’re satisfied, and become satisfied faster because they’re not eating such large amounts of carbohydrate, and also getting more hunger-reducing fat in the diet.

Do reduced-carbohydrate diets increase the risk of heart disease?

I often smile when people bring this up as a reason not to try lower-carbohydrate diets. For some people, you can give them all the proof in the world that lower-carb diets result in far greater weight loss, but because they may not want to acknowledge their effectiveness, they proclaim the heart disease risk the diets cause.

In the context of high- and low-carbohydrate diets, heart disease risk is often determined based on blood levels of LDL cholesterol, HDL cholesterol, triglycerides and glucose. If a diet negatively impacts lipid and glucose levels, it may increase the risk of developing heart disease. Being overweight also increases the risk of developing heart disease, so the fact that low-carbohydrate diets have been shown to be more effective for weight loss suggests they can also improve future health outcomes.

Even so, some people point at lipid levels and suggest that the added fat in the diet will cause problems. In an ideal world, according to conventional thought, a diet should lower LDL cholesterol, raise HDL cholesterol, lower triglycerides and lower glucose levels. Many see the value of the ratio of LDL and HDL as superior to looking at the numbers alone, so if a diet were to equally increase LDL and HDL by similar levels, it would actually improve the LDL/HDL ratio and lower risk.

In addition, those following lower-carbohydrate diets often end up with lower actual LDL particle numbers, a much more predictive measure of heart disease risk, even though the concentration of cholesterol may be higher. Peter Attia has been writing an excellent series of articles on this topic if you’d like more information: The Straight Dope on Cholesterol.

Again, considering the research, how does low-carb compare to low-fat when it comes to lipids and glucose?

In almost every case, HDL cholesterol levels increase in a low-carb diet, far more than from a low-fat diet. In fact, some studies show HDL cholesterol drops on a low-fat diet. HDL cholesterol is seen as protective and, for the most part, the more you have, the better. Saturated fat tends to support higher HDL cholesterol the most from a diet standpoint.

Most times, a slight increase in LDL cholesterol is seen with low-carb, and a reduction is seen with low-fat. However, lower LDL cholesterol by itself is not always good. If the concentration of LDL cholesterol goes down but the number of LDL particles in the blood goes up, it can increase the risk of heart disease.

Triglycerides are another marker to be aware of. Unfortunately, cholesterol gets the bulk of the attention, but elevated triglyceride levels are no less important than understanding cholesterol levels. In fact, comparing triglycerides against HDL (trig/HDL ratio) may be even more predictive of heart disease risk than LDL and HDL comparisons. For triglyceride levels, studies show a dramatic decrease in levels with the use of a low-carbohydrate diet. Carbohydrate consumption increases the production of triglycerides, so lowering carbohydrate levels has a major impact. In some of the studies, triglyceride levels actually went up as a result of following a low-fat diet. If they did go down, the reduction was often unimpressive compared to those on the low-carb diets.

Researchers from the diet trials summarized their findings with conclusions such as:

"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)

"Severely obese subjects with a high prevalence of diabetes or the metabolic syndrome lost more weight during six months on a carbohydrate-restricted diet than on a calorie- and fat-restricted diet, with a relative improvement in insulin sensitivity and triglyceride levels."” (3)

"Compared with a low-fat diet, a low-carbohydrate diet program had better participant retention and greater weight loss. During active weight loss, serum triglyceride levels decreased more and high-density lipoprotein cholesterol levels increased more with the low-carbohydrate diet than with the low-fat diet."” (5)

"The LC diet appears to be an effective method for short-term weight loss in overweight adolescents and does not harm the lipid profile.”"(6)

"...a very low carbohydrate diet is more effective than a low fat diet for short-term weight loss and, over 6 months, is not associated with deleterious effects on important cardiovascular risk factors in healthy women."” (7)

"Despite a threefold higher intake of dietary saturated fat during the CRD, saturated fatty acids in TAG and cholesteryl ester were significantly decreased, as was palmitoleic acid (16:1n-7), an endogenous marker of lipogenesis, compared to subjects consuming the LFD...The results support the use of dietary carbohydrate restriction as an effective approach to improve features of MetS (metabolic syndrome) and cardiovascular risk."” (8)

Are reduced-carbohydrate diets effective for managing blood sugar?

Blood glucose levels are heavily influenced by the amount of carbohydrates in the diet, so it’s no surprise that in the studies comparing low-carb and low-fat diets where glucose was measured, low-carb did better than low-fat at lowering blood glucose levels, sometimes dramatically better. One study also included the use of a Mediterranean diet, and the Mediterranean diet did better than low-carb or low-fat at lowering glucose levels, though low-carb was still superior for improving lipid profiles and weight loss. In fact, when diabetic patients follow a low-carb diet, the drop in blood glucose is even more significant than when those who have normal glucose levels use low-carb. Knowing what research suggests, it’s surprising the American Diabetes Association still recommends a high-carb, low-fat diet. The free meal plan generator on their site came up with a recommended meal plan of 1610 calories, 205 grams of carbs, 88 grams of protein and 55 grams of fat (~50% carb, 20% protein, 30% fat).

Are reduced-carbohydrate diets easier to maintain than calorie-restricted, low-fat diets?

If reduced-carbohydrate diets are more effective for weight loss, improving lipid profiles and managing blood sugar, what about the ability for people to stick with them? Even if they’re effective, they’re only effective when people follow them. The bigger question should be “Are low-carb diets more difficult to sustain than other diets?” According to many of the papers referenced above, those in research studies adhere to low-carb about as well as other diets.

Does that mean they’re easy? Not when people still have carbohydrate-rich processed foods in the house. If someone is to be successful long term, he or she must make a commitment to stay away from the foods that negatively impact their health. That would be the case no matter what type of “diet” individuals eat. However, the reason people are able to more easily fit a lower-carb diet into their lifestyles is that it doesn’t require calorie-counting, starvation or any other issues common with low-calorie, low-fat diets.

The majority of studies on low-fat diets versus low-carb compare a calorie-restricted, low-fat diet against a low-carb, ad libitum (eat as much as you wish) diet. Often, people actually eat fewer calories on the low-carb diet without thinking about it because they’re more satisfied. The bottom line is, according to the evidence, if people wish to change their lifestyle, a reduced-carb approach to eating is much easier to adapt than the low-fat alternative. As the researchers in the Journal of the American Dietetic Association concluded:

"This perception of less hunger and equivalent restraint with a low-carbohydrate/high-protein diet may explain the greater BW loss compared with the high-carbohydrate/low-fat diet."” (15)

Is carbohydrate reduction appropriate for kids?

With the alarming rates of overweight and obesekids, two studies offer some fascinating feedback. Both studies come from The Journal of Pediatrics. In one 12-week study, a group of adolescents were split into two groups. One group was put on a low-fat, low-calorie diet where their daily calorie target was 30% lower than their maintenance level. The other group was put on a diet that limited carbohydrate intake to 20 grams, targeted protein at about a gram per pound of target body weight, and allowed for unlimited total calorie intake. This is key, as it is in many of the other low-carb studies; the low-carb group doesn’t have a calorie limit. In this study, the low-carb group lost an average of 29 pounds compared to the low-fat group that lost just 16 pounds! The low-carb group also had a dramatic drop in triglyceride levels.

The second study was designed with similar nutrition targets and also lasted 12 weeks. The low-carb group lost more than twice as much weight in 12 weeks and also saw a tremendous drop in triglycerides.

Most parents are told their kids need to exercise more and eat less. These two studies beg for a different approach to help control the rates of obesity in youth.

How much carbohydrate is acceptable?

The final question is a personal one: “How much carbohydrate is right for me?” At Life Time, the breakdown of macronutrients for the average person is around 40% carbohydrate, 30% protein and 30% fat. There is nothing magical about these macronutrient levels, other than the fact that they are lower in carbohydrate and higher in protein than the Standard American Diet. It’s a starting point. Someone eating 2000 calories a day would get 200 grams of carbohydrate.

Based on the research, that’s a LOT of carbohydrate and much more than most people would need. However, it’s less than the general population gets. Looking at the research comparing low-fat and low-carb, most of the studies start people with 20 grams of carbohydrates per day, which is what Dr. Atkins encouraged beginning with his first book. However, the misconception is that people should stay there and that is not the case. The method many of the research studies used was to start people at 20 grams or less per day for the first couple weeks and then add in 5 grams more of carbohydrate per day each week. Carbohydrates would continue to be added into the diet until weight loss slowed or other indicators showed that the individual was getting too much carbohydrate.

Though some people with insulin resistance or carbohydrate intolerance should maintain a very-low carbohydrate diet, it is not necessary for most people. It also should not be done without an experienced health care professional’s support, especially for those on glucose-lowering medications.

So is there an ideal range? It’s hard to say at this point. Less than 150 grams a day for most people is likely appropriate. Many find their sweet spot to be between 50 to 100 grams per day. Though people are free to experiment with their diet as they see fit, I would strongly encourage those who are considering a reduced-carbohydrate diet to work with a dietitian.

The approach to modifying your diet depends on your starting point, your current health status, and the appropriate approach for making changes. In our experience, the faster one jumps into a new nutrition plan, the easier it is for them to jump back out of it. In the end, we’re not talking about reducing carbohydrate intake as a way to diet. We’re looking at it as a lifestyle. The goal is to make it something that can be maintained for the rest of your life, so you can maintain the improved lipid profiles, the healthy weight, better energy and lack of focus on dieting. By working with a nutrition professional, you can focus on manageable steps each week to make this a new way of living. After all, if your health improves, the weight starts to come off anyway.

Summary

Random, controlled trials are considered the best way to determine what people should be doing to optimize their health and manage weight. Low-carb diets have a reputation for being only as effective as low-fat diets in weight loss and for increasing the risk of developing heart disease. The random, controlled trials suggest otherwise. As we face the burden of growing health care costs and a decreasing quality of life from our growing waistlines and declining health, we must look at what the evidence suggests based on studies such as these rather than repeating the dietary advice that is conventional or popular.  

Written By Tom Nikkola - Director of Nutrition and Weight Management

This article is not intended for the treatment or prevention of disease, nor as a substitute for medical treatment, nor as an alternative to medical advice. Use of recommendations in this and other articles is at the choice and risk of the reader.

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Reader Comments (22)

Hi Tom, can you confirm that non-starchy vegetables are not included in carb counts? So if you are counting carbs, you're really just looking at what is coming from dairy, starchy veggies, fruit, grains, etc.? Thanks.

July 7, 2012 | Unregistered CommenterMel

@Mel: Non-starchy vegetables still have carbs in them, though far less than starchy vegetables, fruit, grains, etc. If non-starchy carbs are the main/only source of carbs in the diet, it's pretty tough to overdo them, but the non-fiber carbs in non-starchy vegetables still do contribute to the carbs consumed. A little wordy, but hopefully that makes sense.

July 7, 2012 | Unregistered CommenterTom Nikkola

Tom
What about the effectiveness of The Eat To Live diet? Furman touts the benefits of his approach above all
including low carb?
Belinda

July 9, 2012 | Unregistered CommenterBelinda

Hi, Tom. I love all these articles. Thanks for writing them.

I just started the book "Wheat Belly". What do you think of that author's contention that wheat particularly is the culprit, not just carbs in general?

July 9, 2012 | Unregistered CommenterTamara

@ Tamara - Wheat Belly is a good outline of some of the wheat-specific inflammatory and/or addictive properties of this grain (which is quite different from what wheat used to be...)

Check out our interview with the author here: http://lifetime-weightloss.com/blog/2012/1/12/life-time-weight-loss-interview-dr-william-davis-wheat-belly.html

July 9, 2012 | Unregistered CommenterPaul Kriegler, RD/LD

I noticed in the response to a question above the mention of 'non-fiber carbs'. For many years I've enjoyed a popular high fiber cereal, but I've noticed that the amount of total carbs listed on the nutritional information panel is 25g for a 30g, 1/2 cup serving. Because the serving contains 14g of dietary fiber, does this reduce the number of total carbs per serving to 11g? In other words, do dietary fiber carbs count towards one's total carb count?

Thanks!

July 9, 2012 | Unregistered CommenterPhillip M Zeuner

As a diabetic low carb is the most affective way to loss weight because the more carbs I eat, good or bad, the more insilin I need (it is a hormone) the less hormone (insilin) the easy it is for me to loss weight, but the nutritionist at the Dr. says a diabetic needs 45 grams of carbs at each meal for the kidneys, it is very confusing!!

July 9, 2012 | Unregistered CommenterPat

Any advice on the best carbs to include in your diet? Trying to live a low carb lifestyle but have found that dropping my intake too low will cause severe migraines. Curious to your thoughts on the best choices . .

July 10, 2012 | Unregistered CommenterAmmie

For years I worked with my mother-in-law to manage her glucose levels through diet as she was diabetic. I finally convinced her through trial and error that high protein, low carb, lots of non-starch veggies was the answer. So every meal was a salad, large amounts of protein (mostly chicken), and if she just had to have her bread (which she loved) she could have a little piece of bread OR a couple bites potato or rice but not both. Also she was to consume a couple glasses of water at her meal and walk for 30 minutes after. We were able to keep her blood sugars in check for several years. Unfortunately, when she was 88 she took a turn for the worse and ended up in long-term rehab after receiving a pacemaker. We had many arguments with the nutritionist about the high carb diet she insisted my mother-in-law eat resulting in many insulin injections until my increasingly louder fussing finally got the nutritionist's attention and she adhered to what we found worked. Once stablized, my mother-in-law was moved to short term rehab and the same argument commenced with that nutritionist. Unfortunately, it is still being taught to pump carbs into our diabetic society.

July 10, 2012 | Unregistered CommenterMaribell

In the above-mentioned studies, do we know if the weight loss was due to water weight, fat mass or lean body tissue?

July 10, 2012 | Unregistered CommenterMC

Some of the studies do not measure enough detail, however those done by Jeff Volek & Steve Phinney discussed in their book "The Art & Science of Low Carbohydrate Living" measured body composition using DEXA and found the lowest carbohydrate lifestyles lasting longer than 4 weeks show greater preservation of lean mass in the low-carb and greater loss of lean mass on calorie-controlled, low-fat groups. Very interesting (and positive) changes happen when the body is given time to adapt to a higher fat, very low carbohydrate lifestyle.

July 10, 2012 | Unregistered CommenterPaul Kriegler, RD/LD

I'm still a little confused on your answer to the 1st posted question....What exactly are we counting as Carbs? starchy veggies, non-starchy veggies, grains, processed food, dairy, & fruit are all counted as carbs? I thought dairy was protein!

July 10, 2012 | Unregistered CommenterBeverly Perfect

Tom,

What is the difference between a low carb diet and low glycemic diet?

July 10, 2012 | Unregistered CommenterDQ

@Beverly, there are carbohydrates in all of the foods you mentioned and they all count. While dairy, has protein it also has carbohydrates in the form of the milk sugar lactose. One cup of whole milk has 13g of carbohydrates and 8g of protein.

July 10, 2012 | Unregistered CommenterHealthy Living How To

@Belinda: I wouldn't feel comfortable recommending that. It has a minimal amount of protein and very little fat included in the plan, both of which are critical to a healthy metabolism, preservation of muscle tissue, immune support and many other areas of health. I would expect people to lose weight on the plan, as the result of eating mostly raw and cooked vegetables with some starch and nuts included would be a dramatic reduction in calorie intake, but I wouldn't see that as an ideal solution.

July 10, 2012 | Unregistered CommenterTom Nikkola

@Tamra: Thank you. Wheat Belly is an outstanding book. If the URL Paul referenced doesn't work, just type "William Davis" in the search bar at the top of the site and you'll get the interview to come up.

@Phillip: Yes, it would. I'd be wary of high-fiber cereals, though, as they often (not always) have other undesirable ingredients and often contain gluten.

@Pat: I'd ask your nutritionist where he/she is getting the information from. That's just not true. You may want to seek out a different dietitian. I'm sure Paul Kriegler (the RD who commented above) and Anika DeCoster, who writes a lot of the other articles on this site would disagree. I was recently on a cruise (Search "Low Carb Cruise to read about it") and there were many doctors who work with people with Type II diabetes that have seen tremendous success from reducing carb intake. Many of the studies I referenced above were with people who had Type II diabetes. You could click on the image of the table of studies and print out the PDF to bring to your nutritionist as well.

@Ammie: This would be a good question for Paul to weigh in on as well, but from speaking to the experts like Jeff Volek and Steve Phinney, authors of The Art and Science of Low Carbohydrate Living, often times symptoms such as migraines occur due to electrolyte imbalances. When people reduce their carbohydrate intake, they don't hold onto sodium as much, so if they're not using salt in the diet, it can lead to headaches or lightheadedness.

July 10, 2012 | Unregistered CommenterTom Nikkola

@MC: Low-carb diets have a reputation for resulting in losses of mostly water weight, but it isn't true. There will be some water weight loss from the reduced carbs, but it's minor compared to the overall weight loss people see. Often, there is a reduction in inflammation from the diet as well, which can contribute to other water loss, but it's from swelling due to the previous diet rather than just a loss of water. Overall, in studies that have measured fat weight loss versus just body weight loss, lower carb diets still do much better than low-calorie, low-fat diets.

@Beverly: As Healthy Living How To said, there's carbs in all those foods groups. However, real cheese will have a minimal amount of carbohydrates and mostly fat and protein. That said, when people are monitoring their carb intake, they need to be aware of all the carb sources.

@DQ: A low-glycemic diet can still be high in carbs, it just focuses on the use of foods that do not spike insulin levels as much. For example, fructose is very low on the glycemic index, but it is still a carbohydrate. In fact, it's one of the worst because of how the body metabolizes it. Low-glycemic index diets were once thought to be a way to control the effects of insulin, but there's more to the story than just how quickly one's blood sugar rises. Since low-glycemic diets can still result in a HIGH carbohydrate load on the metabolism, they don't have the same effect as reducing overall carb intake.

July 10, 2012 | Unregistered CommenterTom Nikkola

Very interesting post. Most medical doctors working with patients on their weight would agree that low carb is superior to low fat for quick weight loss. Some large medical trials have refuted that - in particular, a study published in JAMA comparing Atkins (low carb), Ornish (low fat) and 2 in-between diets found that reduction in calories mattered, macronutrient composition did not.

Nonetheless, it is interesting to me that a diet with 40% carbohydrates in our country is "low-carb." How did we arrive at the recommendation of 55% of our calories coming from carbs, and anything else is low carb? Medical weight loss programs generally put the carbs between 50 and 100 gm / day. At that level, a mild state of ketosis is likely, and seems to be beneficial to decreasing appetite during weight loss. However, it is critical with this type of diet to get proper amount of protein and micronutrients. In particular, individuals are at risk for low sodium, dehydration, and potassium deficiency. Really with a diet at these levels of carbohydrate, proper medical monitoring is a must.

Less than 50 gm/d of carbohydrate is being used less and less commonly. This will induce a state of brisk ketosis, and really requires close medical supervision, potassium replacement, monitoring of labs and electrocardiogram.

Everybody touts their diet as the best diet, from Wheat Belly to Eat To Live to Atkins to Ornish to You etc. The reality is no diet in a book is right for everybody. Everybody has different food preferences, dietary needs, genetics, situation, reasons for eating, etc. Figuring out the best diet for yourself is the most important part. I agree that a Registered Dietitian is key in helping make significant behavioral changes which are necessary to achieve a significant change in weight. If considering a different style of diet, is it a way you will be willing to eat long-term? A short term diet for weight loss is sure to lead to weight regain if the individual does not continue it.

It is curious that your article does not talk about Mediterranean styles of eating - this might be a great topic for a future post (As would, of course, a review of the other hot trend, Paleo). I'd love your thoughts on these!

July 10, 2012 | Unregistered CommenterEthan Lazarus MD

@Ethan: Good comments. The study you reference in the beginning is one of the studies in the table at the top. You can also download it for free (http://jama.jamanetwork.com/article.aspx?articleid=205916#Abstract). I'm not sure about your comment regarding calories counting, though. The low-carb group lost the most weight and had the most positive effects on lipid levels, yet consumed the most calories of the four groups. Dr. Christopher Garner, who led the study, has a really interesting presentation on YouTube. I think it's called "Is Anyone Winning at Losing?" With regard to electrolytes, it's sodium that most often needs to be consumed as the body excretes a lot more sodium when carbs are low.

July 10, 2012 | Unregistered CommenterTom Nikkola

Tom: Thank you. I stand corrected. I've actually heard Chris lecture several times over the past few years, including this past April when he lectured here in Denver at the American Society of Bariatric Physicians meetings. He spoke on his JAMA trial and gave a very interesting breakdown with subgroup analysis - showing the outliers - who did best and worst in Ornish and Atkins, and went on to suggest that with genetic testing, he could predict, I believe he said with 85% accuracy, which individuals might do best with low fat vs. low carb. Very interesting point of view! My comments were based on the widely-cited Dansinger study from 2005 (http://www.ncbi.nlm.nih.gov/pubmed/15632335) which didn't show a statistical difference between the groups.

Gardner's study did - sorry - I should have looked at your spreadsheet :-) I tend to agree with Gardner's results more than with Dansinger's results. It has been argued that in the Dansinger trial, adherence to the diets was so bad that there wasn't really a big difference between the groups by the end of the trial.

A very interesting approach would be to study similar individuals on full meal replacement with very low carb vs. just low carb. With a medical full meal replacement, I can control the exact composition of the diet - for example, I can do 25 carb, 50 carb, 75 carb, and 100. I am not convinced that there is improved weight loss by dropping from 100 to 25. I am convinced that there is improved weight loss dropping from 55 gm to < 120 gm.

Nestle, the makers of Optifast, one of the popular medical weight loss full meal replacement options, increased their carbohydrates a few years back, so that they are usually 100-120 gm, and no longer rely on ketosis. This was based on a study by Tom Wadden et al. suggesting that ketosis in and of itself does not in fact improve weight loss (http://www.ajcn.org/content/55/4/811.full.pdf). Old study, but this is what the makers of Optifast have used to support their product. Physicians I speak with are heavily divided on the issue of ketosis - many of the most respected physicians in the field still think it's the best thing since sliced bread :-) while many others have raised the carb counts of their approaches to about 100 gm.

Either way, I do feel there is a big difference between 100 gm, 50 gm and 25 gm of carbohydrate, and would be very cautions to recommend counts < 100 gm without proper supervision.

Thanks again for a great article - very thought provoking. I'll check out the you tube video. Always love hearing Dr. Garnder speak.

July 10, 2012 | Unregistered CommenterEthan Lazarus MD

Whenever there is a low-carb vs. low-fat discussion I feel it is missing the boat on what the problem has been with the change in the food supply over the past 100 years or so. Before the cheap processed vegetable oils came into use.. cottonseed, corn oil, soybean etc..the different chemical nature of these fats have dramatically different effects on cellular metabolism than do traditional fats like beef fat, butter, coconut etc.. Some estimates have the United States farm subsidies in the range as high as $350-600 Billion. This results in farmers over-producing these cheap highly poly-unsaturated oils and thus the wide acceptance and consumption of them by humans and in animal feed.

As Chris Masterjohn, Bill Lands, and Ray Peat explain the missing hydrogen and double bonding make these molecules unstable
and highly reactive inside the body sequestering fat and causing other inflammatory disruptions. Societies can do well in terms of weight conrol on high carb diets, Ireland at one point over 100 years ago consumed about 87% of their calories from potatoes. Socities also of course have been known to do well on high fat diets, native Eskimos are sometimes cited as having up to 90 or 95% of calories from whale blubber.

One of, if not the biggest health problem, in america today is that animals being fed soybean oils and other highly unsaturated fats which makes them fatter, allows them to come to market weight faster but also results in a change in the animals lipid profiles from traditionally highly saturated to now much more unsaturated. this can be demonstrated in comparing American chicken and pork fat with that of the Island of Tokelau where they don't feed animals soybean oils. Pork fat in America has recently been revised to 32% poly-unsaturated an alarming 10 times that of Tokelau pig fat which is tested at 3%.. similar numbers occur with the chicken comparsion.

In the opinion of some well respected researchers like Ray Peat and Bill Lands the problem of obesity is poly-unsaturated fat consumption which has increased precipitiously over the same period obesity has. I think when discussing fat vs carb the distinction needs to be made what the p.u.f.a. content on the competing diets are.. vegetarian low fat diets often eliminate the processed vegetable oils and can be succesful and many people struggle on low-carb diets if they increase their linoleic acid content in place of carbs.

July 12, 2012 | Unregistered Commenterdavid ramsey

@David: All great points. The subject of this article, though, was comparing the random, controlled research results of low-fat diets versus low-carb diets. The results are significant when people reduce their carb intake, even without being told specifically which fatty acids they should focus on. That's what makes it so easy for people to start down the right path without complicating things. Once someone is down the path, emphasizing the right kinds of fatty acids can be beneficial as well. Saturated fatty acids, MUFAs and some PUFAs provide a variety of benefits to the diet. It's a good subject for another article. I'm hesitant to use examples of certain cultures at certain points in time as examples, just as I'd avoid using observational studies to determine conclusions.

July 14, 2012 | Unregistered CommenterTom Nikkola

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