Mainstream physicians are still hesitant to recommend low-carb diets because they are usually high in fat, potentially with heart-toxic levels of saturated fats. A recent scientific article supported low-carb eating for heart health.
Carbohydrate restriction shows promise for diabetes, but concerns regarding high saturated fat content of low-carbohydrate diets limit widespread adoption.Objectives
This preplanned ancillary study aimed to determine how diets varying widely in carbohydrate and saturated fat affect cardiovascular disease (CVD) risk factors during weight-loss maintenance.
Methods
After 10–14% weight loss on a run-in diet, 164 participants (70% female; BMI = 32.4 ± 4.8 kg/m2) were randomly assigned to 3 weight-loss maintenance diets for 20 wk. The prepared diets contained 20% protein and differed 3-fold in carbohydrate (Carb) and saturated fat as a proportion of energy (Low-Carb: 20% carbohydrate, 21% saturated fat; Moderate-Carb: 40%, 14%; High-Carb: 60%, 7%). Fasting plasma samples were collected prerandomization and at 20 wk. Lipoprotein insulin resistance (LPIR) score was calculated from triglyceride-rich, high-density, and low-density lipoprotein particle (TRL-P, HDL-P, LDL-P) sizes and subfraction concentrations (large/very large TRL-P, large HDL-P, small LDL-P). Other outcomes included lipoprotein(a), triglycerides, HDL cholesterol, LDL cholesterol, adiponectin, and inflammatory markers. Repeated measures ANOVA was used for intention-to-treat analysis.
Results
Retention was 90%. Mean change in LPIR (scale 0–100) differed by diet in a dose-dependent fashion: Low-Carb (–5.3; 95% CI: –9.2, –1.5), Moderate-Carb (–0.02; 95% CI: –4.1, 4.1), High-Carb (3.6; 95% CI: –0.6, 7.7), P = 0.009. Low-Carb also favorably affected lipoprotein(a) [–14.7% (95% CI: –19.5, –9.5), –2.1 (95% CI: –8.2, 4.3), and 0.2 (95% CI: –6.0, 6.8), respectively; P = 0.0005], triglycerides, HDL cholesterol, large/very large TRL-P, large HDL-P, and adiponectin. LDL cholesterol, LDL-P, and inflammatory markers did not differ by diet.
Conclusions
A low-carbohydrate diet, high in saturated fat, improved insulin-resistant dyslipoproteinemia and lipoprotein(a), without adverse effect on LDL cholesterol. Carbohydrate restriction might lower CVD risk independently of body weight, a possibility that warrants study in major multicentered trials powered on hard outcomes.
Parker here. These findings are no surprise to me.
Steve Parker, M.D.
PS: The Advanced Mediterranean Diet (2nd Ed.) includes a low-carb option.
“If you’re looking to improve your heart health, you may want to try eating a low-carb, high-fat Mediterranean diet. Why? Because a new study published in The American Journal of Clinical Nutrition found that eating a low-carb (no more than 20% of daily calories from carbs), the high fat-style Mediterranean diet may reduce the risk of cardiovascular disease (CVD). For the study, obese study participants reported both improved insulin resistance and cholesterol levels compared to those who ate a moderate carb (40%) or high carb (60%) diet over a five-month period.”
Steve Parker, M.D.
PS: The Ketogenic Mediterranean Diet is obviously low-carb, and is included in both The Advanced Mediterranean Diet (2nd Ed.) and Conquer Diabetes and Prediabetes.
Posted onJuly 13, 2020|Comments Off on How Can Low-Carb Diets Be Better Than Others for Weight Loss?
Sous vide chicken and sautéed sugar snap peas. This meal fits into a low-carb or ketogenic diet.
Low-carbohydrate diets help many folks, but not all, lose excess fat weight. When low-carb diets help, it may be related to Total Energy Expenditure (TEE). When you read “energy,” think calories. TEE is a combination of calories needed for 1) basic life processes (i.e., basal metabolic rate, as needed to maintain heart beats, breathing, steady body heat, growth and repair of tissues, etc.), 2) processing of ingested food (dietary thermogenesis), and 3) physical exercise.
Here’s the abstract of an article in The Journal of Nutrition that examines the headline question. It’s complicated and I haven’t read the full study yet.
Many obesity experts believe that to lose excess fat weight, you have to ingest fewer calories than you burn on a daily basis for physical exercise and basal metabolic rate. This creates a calorie (energy) deficit. Your body satisfies that deficit by converting fat tissue to weightless energy. The authors of the study at hand are essentially saying that, after 2-3 weeks, a low-carb diet “revs up your metabolism” to burn more calories. That can help you lose weight or maintain weight loss, unless you over-eat.
Here you go, nutrition nerds:
Background
The effect of macronutrient composition on total energy expenditure (TEE) remains controversial, with divergent findings among studies. One source of heterogeneity may be study duration, as physiological adaptation to lower carbohydrate intake may require 2 to 3 wk.
Objective
We tested the hypothesis that the effects of carbohydrate [expressed as % of energy intake (EI)] on TEE vary with time.
Methods
The sample included trials from a previous meta-analysis and new trials identified in a PubMed search through 9 March 2020 comparing lower- and higher-carbohydrate diets, controlled for EI or body weight. Three reviewers independently extracted data and reconciled discrepancies. Effects on TEE were pooled using inverse-variance-weighted meta-analysis, with between-study heterogeneity assessed using the I2 statistic. Meta-regression was used to quantify the influence of study duration, dichotomized at 2.5 wk.ResultsThe 29 trials ranged in duration from 1 to 140 d (median: 4 d) and included 617 participants. Difference in carbohydrate between intervention arms ranged from 8% to 77% EI (median: 30%). Compared with reported findings in the prior analysis (I2 = 32.2%), we found greater heterogeneity (I2 = 90.9% in the reanalysis, 81.6% in the updated analysis). Study duration modified the diet effect on TEE (P < 0.001). Among 23 shorter trials, TEE was reduced on lower-carbohydrate diets (−50.0 kcal/d; 95% CI: −77.4, −22.6 kcal/d) with substantial heterogeneity (I2 = 69.8). Among 6 longer trials, TEE was increased on low-carbohydrate diets (135.4 kcal/d; 95% CI: 72.0, 198.7 kcal/d) with low heterogeneity (I2 = 26.4). Expressed per 10% decrease in carbohydrate as %EI, the TEE effects in shorter and longer trials were −14.5 kcal/d and 50.4 kcal/d, respectively. Findings were materially unchanged in sensitivity analyses.
Conclusions
Lower-carbohydrate diets transiently reduce TEE, with a larger increase after ∼2.5 wk. These findings highlight the importance of longer trials to understand chronic macronutrient effects and suggest a mechanism whereby lower-carbohydrate diets may facilitate weight loss.
This finding supports a prediction of the carbohydrate-insulin model and suggests a mechanism whereby dietary carbohydrate reduction could aid in the prevention and treatment of obesity. According to this model, the high insulin-to-glucagon ratio with a diet high in glycemic load (mathematical product of glycemic index and carbohydrate amount) shifts the partitioning of metabolic fuels from oxidation in lean tissue to storage in adipose tissue. If the effects observed here persist over the long term, then reducing dietary carbohydrate intake by half from 60% of energy intake (a typical level for low-fat diets) would increase energy expenditure by ∼150 kcal/d, counterbalancing (if not compensated for by other factors) much of the secular increase in energy intake thought by some to underlie the obesity epidemic.
Reducing carbohydrate content of breakfast improved weight loss on a calorie-restricted Mediterranean diet. Both diets in the study at hand were calorie restricted Mediterranean diets but only one of them restricted carbs at breakfast. Unfortunately the abstract does not mention the degree of calorie restriction nor the the AM carb restriction.
From the abstract of the study at hand:
Methods
Seventy overweight/obese individuals were randomized to two hypocaloric dietary regimens: one Mediterranean diet (Med-D) and one morning carbohydrate-restriction diet (MCR-D). Participants assigned to the MCR-D were permitted to consume a breakfast low in carbohydrate content, whereas typical Mediterranean morning meals were allowed in the Med-D group. Both diets were identical from midday on. Participants were followed over a period of 2 mo.
Results
Individuals in both groups achieved significant reductions in body weight, body mass index, waist circumference, and body fat mass. These reductions were more pronounced in the MCR-D than in the Med-D group (all P < 0.001). More participants in the MCR-D group achieved loss of 5% to 10% of body weight by the end of the first month, as well as 5% to 10% and >10% of body weight by the end of the second month (all P < 0.001). All participants achieved loss of ≥5% baseline body weight by the end of the intervention. Both groups achieved similar reductions in fasting serum glucose, glycated hemoglobin, and serum triacylglycerols as well as improvement in insulin sensitivity. Individuals in the Med-D group showed reductions in total and low-density lipoprotein cholesterol, whereas no such effect was observed in the MCR-D group.
Conclusions
Integration of morning carbohydrate restriction into a Mediterranean-type hypocaloric diet resulted in greater weight loss while retaining metabolic benefits in glycemia-related parameters.
Posted onFebruary 21, 2020|Comments Off on Low-Carb Diet NOT Linked to Psychological Disorders
…at least in Iranians. From Nutrition Journal:
Adherence to the low carbohydrate diet, which contains high amount of fat and proteins but low amounts of carbohydrates, was not associated with increased odds of psychological disorders including depression, anxiety and psychological distress. Given the cross-sectional nature of the study which cannot reflect causal relationships, longitudinal studies, focusing on types of macronutrients, are required to clarify this association.
The short answer? We don’t know the answer to either of those questions.
Low-carb salad
The gut bacteria (aka microbiome) seem to be able to decrease or increase inflammation that could cause or exacerbate Alzheimer’s dementia. The microbiome’s effect on inflammation depends on the species of bacteria present, and the amount of those bacteria. At least one study found that Alzheimer’s patients have a greater abundance of the pro-inflammatory species and less of the anti-inflammatory species, compared to other folks.
Researchers with Wake Forest School of Medicine tried to find answers to the questions in the title of this post. (Click for full text.) They studied 17 experimental subjects, average age 64, who had mild cognitive impairment (11) or “cogni/subjective memory complaints” (6). God bless them for submitting to three spinal taps apiece. The experimental diets were 1) Mediterranean-Ketogenic (under 20 g carb/day), or 2) Low-fat American Heart Association diet (under 40 g fat/day). Participants were on each diet for six weeks.
The investigators didn’t find anything useful for those of us trying today to avoid Alzheimer’s or prevent the progression of mild cognitive impairment to dementia. Their bottom line is, “The data suggest that specific gut microbial signatures may depict [characterize] the mild cognitive impairment and that the modified Mediterranean-ketogenic diet can modulate the gut microbiome and metabolites in association with improved Alzheimer’s disease biomarkers in cerebrospinal fluid.”
So we won’t know for several more years, if ever, whether intentional modification of diet will “improve” our gut microbiomes, leading to lower risk of dementia.
What we have known for many year, however, is that the traditional Mediterranean diet is linked to lower risk of Alzhiemer’s dementia.
For more details, see Science Daily:
In a small pilot study, the researchers identified several distinct gut microbiome signatures — the chemicals produced by bacteria — in study participants with mild cognitive impairment (MCI) but not in their counterparts with normal cognition, and found that these bacterial signatures correlated with higher levels of markers of Alzheimer’s disease in the cerebrospinal fluid of the participants with MCI.
Through cross-group dietary intervention, the study also showed that a modified Mediterranean-ketogenic diet produced changes in the gut microbiome and its metabolites that correlated with reduced levels of Alzheimer’s markers in the members of both study groups.
When you read “total energy expenditure” below, it may make more sense if you substitute “calories burned per day.” If you burn your food calories, they don’t end up as stored fat on your body,
“In this controlled feeding trial over 20 weeks, we found that total energy expenditure was significantly greater in participants assigned to a low carbohydrate diet compared with high carbohydrate diet of similar protein content. In addition, pre-weight loss insulin secretion might modify individual response to this diet effect. Taken together with preliminary reports on activation of brain areas involved in food cravings and circulating metabolic fuel concentration, results of the current Framingham State Food Study (FS)2 substantiate several key predictions of the carbohydrate-insulin model. Regardless of the specific mechanisms involved, the study shows that dietary quality can affect energy expenditure independently of body weight, a phenomenon that could be key to obesity treatment, as recently reviewed.”
Julia Belluz has interesting article at Vox regarding low-fat and low-carb diet success over the course of 12 months. Her focus is on a few individuals who participated and were outliers.
As I read this, I was reminded that successful long-term weight management starts and ends in the kitchen. It also took me back to 2009, when I determined that low-carb diets were just as legitimate as low-fat.
I don’t recall the author mentioning the typical pattern with 12-month weight loss studies: most folks lose significant weight in the first few month, then at six months they start gaining it back. Cuz they go back to their old eating habits. Sure, diets don’t work………..if you don’t follow them.
From Ms. Belluz:
As a longtime health reporter, I see new diet studies just about every week, and I’ve noticed a few patterns emerge from the data. In even the most rigorous scientific experiments, people tend to lose little weight on average. All diets, whether they’re low in fat or carbs, perform about equally miserably on average in the long term.
But there’s always quite a bit of variability among participants in these studies.Just check out this chart from a fascinating February study called DIETFITS, which was published in JAMA by researchers at Stanford.
The randomized controlled trial involved 609 participants who were assigned to follow either a low-carb or a low-fat diet, centered on fresh and high-quality foods, for one year. The study was rigorous; enrollees were educated about food and nutrition at 22 group sessions. They were also closely monitored by researchers, counselors, and dietitians, who checked their weight, waist circumference, blood pressure, cholesterol, and other metabolic measures throughout the year.
Overall, dieters in both groups lost a similar amount of weight on average — 11 pounds in the low-fat group, 13 pounds in the low-carb group — suggesting different diets perform comparably. But as you can see in the chart, hidden within the averages were strong variations in individual responses. Some people lost more than 60 pounds, and others gained more than 20 during the year.
That’s a guacamole deviled egg. Photo Copyright: Steve Parker
In 2014 Howard Stern interviewed Bryan Cranston and asked how he lost weight so quickly for his role as Walter White on Breaking Bad:
“Stern: When you had chemo and was getting sick playing the part of Walter White, in order to go through rapid weight loss you deliberately didn’t eat for 10 days? True or false?
Cranston: False.
Stern: How’d you lose all that weight?
Cranston: No carbohydrates. I just took out all the carbohydrates.
Stern: How much weight did you drop?
Cranston: 16 pounds, in ten days.
Stern: Painful?
Cranston: No. The first three days are really hard, ’cause your body’s changing and craving sugar and wants, you know, and then you deprive it of the sugar and it starts burning fat.”
