Low Fat Diets (Review)

[WillBrink]

This large meta-analysis from the NIH confirms what many learn the hard way, that low fat diets are not superior to other approaches. I consider low fat diets a poor approach and a negative to health long term.


Effect of low-fat diet interventions versus other diet interventions on long-term weight change in adults: a systematic review and meta-analysis

Summary

Background

The effectiveness of low-fat diets for long-term weight loss has been debated for decades, with many randomised controlled trials (RCTs) and recent reviews giving mixed results. We aimed to summarise the large body of evidence from RCTs to determine whether low-fat diets contribute to greater weight loss than participants' usual diet, low-carbohydrate diets, and other higher-fat dietary interventions.
Methods

We did a systematic review and random effects meta-analysis of RCTs comparing the long-term effect (≥1 year) of low-fat and higher-fat dietary interventions on weight loss by searching MEDLINE, Embase, Cochrane Central Register of Controlled Trials (CENTRAL), and Cochrane Database of Systematic Reviews to identify eligible trials published from database inception up until July 31, 2014. We excluded trials if one intervention group included a non-dietary weight loss component but the other did not, and trials of dietary supplements or meal replacement drink interventions. Data including the main outcome measure of mean difference in weight change between interventions, and whether interventions were intended to lead to weight loss, weight maintenance, or neither, were extracted from published reports. We estimated the pooled weighted mean difference (WMD) with a DerSimonian and Laird random effects method.

Findings

3517 citations were identified by the search and 53 studies met our inclusion criteria, including 68 128 participants (69 comparisons). In weight loss trials, low-carbohydrate interventions led to significantly greater weight loss than did low-fat interventions (18 comparisons; WMD 1·15 kg [95% CI 0·52 to 1·79]; I2=10%). Low-fat interventions did not lead to differences in weight change compared with other higher-fat weight loss interventions (19 comparisons; WMD 0·36 kg [−0·66 to 1·37; I2=82%), and led to a greater weight decrease only when compared with a usual diet (eight comparisons; −5·41 kg [−7·29 to −3·54]; I2=68%). Similarly, results of non-weight-loss trials and weight maintenance trials, for which no low-carbohydrate comparisons were made, showed that low-fat versus higher-fat interventions have a similar effect on weight loss, and that low-fat interventions led to greater weight loss only when compared with usual diet. In weight loss trials, higher-fat weight loss interventions led to significantly greater weight loss than low-fat interventions when groups differed by more than 5% of calories obtained from fat at follow-up (18 comparisons; WMD 1·04 kg [95% CI 0·06 to 2·03]; I2=78%), and when the difference in serum triglycerides between the two interventions at follow-up was at least 0·06 mmol/L (17 comparisons; 1·38 kg [0·50 to 2·25]; I2=62%).

Interpretation

These findings suggest that the long-term effect of low-fat diet intervention on bodyweight depends on the intensity of the intervention in the comparison group. When compared with dietary interventions of similar intensity, evidence from RCTs does not support low-fat diets over other dietary interventions for long-term weight loss.

http://www.thelancet.com/journals/la...367-8/abstract

[gbullock32]

So pretty much low-fat yields no advantage in terms of long term weight loss, and it is still down to caloric deficit.

[WillBrink]

So pretty much low-fat yields no advantage in terms of long term weight loss, and it is still down to caloric deficit.

From a strictly weight loss POV, yup, that about sums it up. There may be some metabolic advantages to other approaches - even when cals are identical - but caloric deficit still the major variable. All things being equal, high protein, moderate fat of the right types and ratios, and moderate/low carb intakes from high fiber/nutrient dense sources is the way to go for healthy long term fat loss.

[likeafish]

What is considered high, moderate and low for each macro?

Is low fat a range with the bottom limit being the lowest recommended intake, or below it? I've always thought of the recommended protein intake for gaining as also being moderate protein, high being excessive, like 1.5+xbw. Or is there an "extremely high/low" category?

[mccyjcb]

I think "low" refers to 0.2g/lb of bodyweight as opposed to the accepted range of 0.4g/lb - 0.6g/lb.

[blue9steel]

I tried low fat pretty seriously back in the 90s and it did not work well for me at all. It's been nice for the science to finally catch up in the last ten years or so.

[ErikTheElectric]

Still eating low fat + High carb as that has worked the best for me. Take studies with a grain of salt.. Not every individual leads the same lifestyle, trains the same way, and handles all nutrients the same way.

[NBThing]

October 30 - New study on low-carb being better http://www.theguardian.com/lifeandst...jor-new-report

October 29 - New study on low-fat being better http://www.telegraph.co.uk/news/heal...udy-finds.html

LOL.

[WillBrink]

Still eating low fat + High carb as that has worked the best for me. Take N =1 subjective anecdotal comments on forums with a grain of salt.. Not every individual leads the same lifestyle, trains the same way, and handles all nutrients the same way.

Fixed it for ya. But seriously, if that approach works for you, drive on. However, studies always trump N =1 subjective anecdotal feedback and always will, as they should. It's obvious from the "real world" experience and the studies, people can lose weight on a high carb/low fat approach, and this review does not say otherwise. Read carefully...

[WillBrink]

October 30 - New study on low-carb being better http://www.theguardian.com/lifeandst...jor-new-report

October 29 - New study on low-fat being better http://www.telegraph.co.uk/news/heal...udy-finds.html

LOL.

Hey red, guess what, the telegraph and guardian are not sci/med journals. Leave the science to scientists and work on getting more red.

[NBThing]

Hey red, guess what, the telegraph and guardian are not sci/med journals. Leave the science to scientists and work on getting more red.

Guess what, for someone "reviewing" a diet, you seem pretty ignorant and lacking rationale. That's first.

Second, you do understand that these articles are reporting on the studies conducted by universities? They don't have any involvement in the studies themselves. I think even 3rd graders understand that there's no relation between the two. So I'm not sure if you're aware, but The Guardian and Telegraph are news sources. They laid out the information in layman terms and quoted the lead researchers' conclusions of the study.

Here are alternative sources fro the same two studies for those who are lazy. Would you like to argue?

http://www.thelancet.com/pdfs/journa...15)00367-8.pdf

http://www.hsph.harvard.edu/news/pre...m-weight-loss/

Hey, scientist, I think leave reviewing diets to people who at least have some common sense. Go finish 3rd grade first, baldy.

How's my work on more red? You need more, mofo?

[Mrpb]

I'll throw in my copy-paste as well.

"Trials show weight loss in the short-term irrespective of whether the diet is low CHO or balanced. There is probably little or no difference in weight loss and changes in cardiovascular risk factors up to two years of follow-up when overweight and obese adults, with or without type 2 diabetes, are randomised to low CHO diets and isoenergetic balanced weight loss diets."

Low Carbohydrate versus Isoenergetic Balanced Diets for Reducing Weight and Cardiovascular Risk: A Systematic Review and Meta-Analysis
http://journals.plos.org/plosone/art...l.pone.0100652

"Significant weight loss was observed with any low-carbohydrate or low-fat diet. Weight loss differences between individual named diets were small. This supports the practice of recommending any diet that a patient will adhere to in order to lose weight."

Comparison of Weight Loss Among Named Diet Programs in Overweight and Obese Adults, A Meta-analysis
http://jama.jamanetwork.com/article....icleid=1900510

A Diet by Any Other Name Is Still About Energy
http://jama.jamanetwork.com/article....icleid=1900489

If you're comparing diets that match sufficient protein intake, you don't lose fat more quickly with lower carbs (yes, even at keto levels). This has been demonstrated repeatedly:

"Body-weight loss and weight-maintenance depends on the high-protein, but not on the 'low-carb' component of the diet, while it is unrelated to the concomitant fat-content of the diet." http://www.ncbi.nlm.nih.gov/pubmed/22935440

"KLC [ketogenic low-carb] and NLC [non-ketogenic low-carb] diets were equally effective in reducing body weight and insulin resistance, but the KLC diet was associated with several adverse metabolic and emotional effects. The use of ketogenic diets for weight loss is not warranted." http://www.ncbi.nlm.nih.gov/pubmed/16685046

Also see the results of this meta-analysis of 23 randomized controlled trials (mean carb proportion in the LC groups was 23% of total kcals):

"Reductions in body weight, waist circumference and other metabolic risk factors were not significantly different between the 2 diets." http://www.ncbi.nlm.nih.gov/pubmed/23035144

Regarding diet comparisons in general:

"Significant weight loss was observed with any low-carbohydrate or low-fat diet. Weight loss differences between individual named diets were small. This supports the practice of recommending any diet that a patient will adhere to in order to lose weight." http://www.ncbi.nlm.nih.gov/pubmed/25182101

[WillBrink]

Guess what, for someone "reviewing" a diet, you seem pretty ignorant and lacking rationale. That's first.

Second, you do understand that these articles are reporting on the studies conducted by universities? They don't have any involvement in the studies themselves. I think even 3rd graders understand that there's no relation between the two. So I'm not sure if you're aware, but The Guardian and Telegraph are news sources. They laid out the information in layman terms and quoted the lead researchers' conclusions of the study.

Here are alternative sources fro the same two studies for those who are lazy. Would you like to argue?

http://www.thelancet.com/pdfs/journa...15)00367-8.pdf

http://www.hsph.harvard.edu/news/pre...m-weight-loss/

Hey, scientist, I think leave reviewing diets to people who at least have some common sense. Go finish 3rd grade first, baldy.

How's my work on more red? You need more, mofo?

Nope. I added some red for your idiotic comments. Carry on red.

[WillBrink]

I'll throw in my copy-paste as well.

"Significant weight loss was observed with any low-carbohydrate or low-fat diet. Weight loss differences between individual named diets were small. This supports the practice of recommending any diet that a patient will adhere to in order to lose weight?"

Sums up the real T well. There's some approaches that may have an edge in terms of satiety, preservation of LBM, health, etc, but that's the real T on the big picture.