Study Abstracts vs Study Details

Sometimes a study’s abstract doesn’t reflect the results. Here’s one example (Am J Clin Nutr. 1996 Feb;63(2):174-8. Similar weight loss with low- or high-carbohydrate diets. Golay A1, Allaz AF, Morel Y, de Tonnac N, Tankova S, Reaven G.). The abstract states:

There was no significant difference in the amount of weight loss in response to diets containing either 15% (8.9 +/- 0.6 kg) or 45% (7.5 +/- 0.5 kg) carbohydrate.

The actual results table shows a difference:

The Lower Carb (15%) resulted in:

  • Larger weight loss (8.3% vs 7.4%)
  • Larger fat loss (17.7% vs 16.8%)
  • Larger reduction in waist-to-hip ratio (0.3 vs 0.2)

The Lower carb diet also resulted in improved:

  • Fasting plasma glucose  decreased significantly
  • insulin  decreased significantly
  • cholesterol  decreased significantly
  • triacylglycerol concentrations  decreased significantly

Low carb for the win again!

Calories In Calories Out and Macros Ratios

An interesting study on macros ratios which compared high carbohydrates to high protein impacts (Layman DK, Boileau RA, Erickson DJ, Painter JE, Shiue H, Sather C, Christou DD. A reduced ratio of dietary carbohydrate to protein improves body composition and blood lipid profiles during weight loss in adult women. J Nutr. 2003 Feb;133(2):411-7.).

This study examined the efficacy of two weight loss diets with modified CHO/protein ratios to change body composition and blood lipids in adult women.

Women (n = 24; 45 to 56 y old) with body mass indices >26 kg/m(2) were assigned to either a CHO Group consuming a diet with a CHO/protein ratio of 3.5 (68 g protein/d) or a Protein Group with a ratio of 1.4 (125 g protein/d). Diets were isoenergetic, providing 7100 kJ/d, and similar amounts of fat ( approximately 50 g/d).

After consuming the diets for 10 wk, the CHO Group lost 6.96 +/- 1.36 kg body weight and the Protein Group lost 7.53 +/- 1.44 kg. Weight loss in the Protein Group was partitioned to a significantly higher loss of fat/lean (6.3 +/- 1.2 g/g) compared with the CHO Group (3.8 +/- 0.9).

Both groups had significant reductions in serum cholesterol ( approximately 10%), whereas the Protein Group also had significant reductions in triacylglycerols (TAG) (21%) and the ratio of TAG/HDL cholesterol (23%). Women in the CHO Group had higher insulin responses to meals and postprandial hypoglycemia, whereas women in the Protein Group reported greater satiety.

This study demonstrates that increasing the proportion of protein to carbohydrate in the diet of adult women has positive effects on body composition, blood lipids, glucose homeostasis and satiety during weight loss.

The high carbohydrate group lost 7 kg of weight but about half of the loss was lean body mass. The high protein group maintained most of their lean body mass.

 

Too Much Protein?

Here’s an interesting study on protein overfeeding (Jose Antonio, Corey A Peacock, Anya Ellerbroek, Brandon Fromhoff and Tobin Silver. The effects of consuming a high protein diet (4.4 g/kg/d) on body composition in resistance-trained individuals. Journal of the International Society of Sports Nutrition 2014:11:19.).

The HP group consumed significantly more protein and calories pre vs post (p < 0.05). Furthermore, the HP group consumed significantly more protein and calories than the CON (p < 0.05). The HP group consumed on average 307 ± 69 grams of protein compared to 138 ± 42 in the CON. When expressed per unit body weight, the HP group consumed 4.4 ± 0.8 g/kg/d of protein versus 1.8 ± 0.4 g/kg/d in the CON. There were no changes in training volume for either group. Moreover, there were no significant changes over time or between groups for body weight, fat mass, fat free mass, or percent body fat.

Consuming 5.5 times the recommended daily allowance of protein has no effect on body composition in resistance-trained individuals who otherwise maintain the same training regimen. This is the first interventional study to demonstrate that consuming a hypercaloric high protein diet does not result in an increase in body fat.

Here’s the table for the data (BW= Body Weight, FFM = Fat Free Mass, FM = Fat Mass, BF = Body Fat percentage).

Body composition

Control

HP

Pre

Post

Change

Pre

Post

Change

BW (kg)

76.4 ± 9.9

77.2 ± 9.9

0.8 ± 1.6

71.8 ± 12.2

73.5 ± 12.5

1.7 ± 1.9

FFM (kg)

65.2 ± 11.7

66.5 ± 11.7

1.3 ± 2.0

59.5 ± 10.9

61.4 ± 11.6

1.9 ± 2.4

FM (kg)

11.2 ± 4.7

11.4 ± 5.0

0.3 ± 4.7

12.3 ± 7.0

12.0 ± 6.2

−0.2 ± 2.2

% BF

15.1 ± 6.9

14.2 ± 6.9

−0.9 ± 1.7

16.9 ± 8.3

16.3 ± 7.5

−0.6 ± 2.6

The High Protein group actually lose body fat and gained fat free mass in spite of overeating Protein and calories.

From the paper:

The results of the current investigation do not support the notion that consuming protein in excess of purported needs results in a gain in fat mass. Certainly, this dispels the notion that ‘a calorie is just a calorie.’ That is, protein calories in ‘excess’ of requirements are not metabolized by the body in a manner similar to carbohydrate.

 

LDL Increases During Massive Weight Losses

Very Low Calorie diets can cause LDL numbers to increase temporarily (Am J Clin Nutr. 1991 Jun;53(6):1404-10. The transient hypercholesterolemia of major weight loss. Phinney SD, Tang AB, Waggoner CR, Tezanos-Pinto RG, Davis PA.).

Abstract

Serum lipoproteins, body composition, and adipose cholesterol contents of six obese women were studied during and after major weight loss by very-low-calorie diets (VLCDs). Subjects started at 168 +/- 11% of ideal body weight, lost 30.3 +/- 3.7 kg in 5-7 mo, followed by 2+ mo in weight maintenance. Serum cholesterol fell from a prediet (baseline) value of 5.49 +/- 0.32 to 3.62 +/- 0.31 mmol/L (P less than 0.01) after 1-2 mo of VLCDs (nadir), after which it rose to 5.95 +/- 0.36 mmol/L (peak, P less than 0.01 compared with nadir and baseline) as weight loss continued. With weight maintenance, serum cholesterol fell to 4.92 +/- 0.34 mmol/L (P less than 0.05 compared with peak). Adipose cholesterol content did not change in peripheral (arm and leg) biopsy sites but rose significantly in abdominal adipose tissue with weight loss. We conclude that major weight loss was associated with a late rise in serum cholesterol, possibly from mobilization of adipose cholesterol stores, which resolved when weight loss ceased.

Here is a second paper on the same issue (Al Dahmani, Khaled Mohammed et al. Transient severe hypercholesterolemia following bariatric surgery treated successfully with increased food intake. Nutrition , Volume 32 , Issue 3 , 394 – 396).

…a case of transient severe hypercholesterolemia after bariatric surgery treated successfully with increased food intake. A 25-y-old policeman who had sleeve gastrectomy for morbid obesity 10 mo previously presented with generalized weakness, constipation, and significant weight loss after severe dietary restriction. All his preoperative and prior investigations were normal. Further investigation revealed severe total and low-density lipoprotein hypercholesterolemia. After all other causes of secondary hypercholesterolemia were excluded, a diagnosis of starvation-induced hypercholesterolemia was made. The patient was therefore started on a normal mixed diet gradually increased to achieve satiation. His dietary intake, body weight, and lipid profile were monitored over a 3-mo period. Eventually his symptoms abated, weight increased, and lipid profile returned back to normal levels. Although dietary management of failed weight loss after bariatric surgery is the main priority for health professionals, this case illustrates the possible harm of severe dietary restriction after surgery and the need for judicious dietary and nutritional management.

On-Line Calculators

Our Calculators

  • Keto Calculator – Calculates PSMF, Zone, Standard American Diet (SAD) , keto maintenance macros, extended fasting estimator, body fat (Calculated and ideal), and genetic muscular potential.
  • Lipids Calculator – Calculates ratios and indices related to blood lipid numbers.

Other Calculators

 

Hazard Ratios for LDL Particle Sizes

There are different types of LDL particles. They are classified by at least two phenotypes (A and B).

Phenotype B is associated with heart disease (LDL subclass phenotypes and triglyceride metabolism in non-insulin-dependent diabetes. K R Feingold, C Grunfeld, M Pang, W Doerrler and R M Krauss. Arteriosclerosis, Thrombosis, and Vascular Biology. 1992;12:1496-1502, originally published December 1, 1992).

A common, heritable phenotype characterized by the predominance of small, dense LDL particles (LDL subclass phenotype B) is associated with relatively increased concentrations of plasma triglycerides, reduced levels of high density lipoprotein, and increased risk of coronary artery disease in comparison with subjects with larger LDL (LDL subclass phenotype A).

Further:

The LDL B phenotype was associated with higher plasma triglyceride levels and a trend toward lower high density lipoprotein cholesterol levels compared with the LDL A phenotype in the NIDDM subjects, as has been previously observed in control groups.

Indices of diabetic control, such as fasting and hemoglobin A1 levels, were similar regardless of LDL phenotype pattern, suggesting that glycemic control was not likely to account for the increase in the LDL B phenotype. In both control and NIDDM subjects, the clearance of triglyceride-rich lipoproteins was slowed in the subjects with the LDL phenotype B compared with those with the A phenotype.

The mix of Phenotype A and Phenotype B LDL particles can be determined from other blood numbers (The American Journal of Cardiology Volume 94, Issue 2, 15 July 2004, Pages 219-222. Accuracy of the triglyceride to high-density lipoprotein cholesterol ratio for prediction of the low-density lipoprotein phenotype B. Viktor Hanak MD, Julian Munoz MD MSPH, Joe Teague MD, Alfred Stanley Jr. MD. Vera Bittner MD MSPHc):

A triglyceride/HDL cholesterol ratio of 3.8 divided the distribution of LDL phenotypes with 79% (95% confidence interval [CI] 74 to 83) of phenotype B greater than and 81% (95% CI 77 to 85) of phenotype A less than the ratio of 3.8. The ratio was reliable for identifying LDL phenotype B in men and women.

I created an on-line lipids calculator to calculate the number from blood test results.

See also (Why LDL-Cholesterol May Be Overestimated on a Low-Carb, High-Fat (LCHF) Diet).

Insulin Response to Various Grains

A study looked at the insulin response to 50 g of carbohydrates of various grains (Postprandial glucose, insulin, and incretin responses to grain products in healthy subjects. Katri S Juntunen Leo K Niskanen Kirsi H Liukkonen Kaisa S Poutanen Jens J Holst Hannu M Mykkänen. The American Journal of Clinical Nutrition, Volume 75, Issue 2, 1 February 2002, Pages 254–262). Here’s the Insulin Response:

That is quite a bit of difference between the peak for Wheat Bread (at 250) and Whole Meal Pasta (about half at around 125). If you are attempting to minimize Insulin response that could be a big difference.

 

 

Side Effect of Bariatric Surgery – Part 2

In Part 1 we looked at the blood sugar response of some bariatric surgery patients. Here’s another paper on the subject which has some actionable suggestions for dealing with this situation (Hypoglycemia after gastric bypass: An emerging complication. Cleveland Clinic Journal of Medicine. 2017 April;84(4):319-328. Author(s): Richard Millstein, DO Helen M. Lawler, MD). The article indicates that:

  • 671,959 patients underwent gastric bypass procedures in the United States from 2003 to 2008.
  • The mean time from gastric bypass to documented hypoglycemia is about 28 months.
  • Serious symptoms, including needing third-party assistance, the prevalence was 11.6%.
  • Roux-en-Y patients who wore a continuous glucose monitor for 86 months after surgery and found that 38% had hypoglycemia.

The article suggests various treatments.

 

Side Effect of Bariatric Surgery – Part 1

Part 2 continues here.

A friend told me about a side effect of bariatric surgery (Post-gastric bypass hypoglycemia: A serious complication of bariatric surgery).

One long-term risk is the development of postprandial hypoglycemia. This phenomenon was first described in the literature in 2005. The prevalence still remains unknown, but as endocrinologists we will undoubtedly be seeing more of these patients. Hypoglycemia typically does not present until 2 to 3 years after gastric bypass surgery.

These hypoglycemic episodes are characterized by low blood sugars that occur 2 to 3 hours after a meal. Fasting hypoglycemia is typically not seen. The etiology seems to be excessive insulin secretion in response to the meal. It is well documented that patients are more insulin sensitive after gastric bypass surgery, but the pathophysiology of these specific patients who develop hypoglycemia remains unclear.

It is hypothesized that it may be related to elevations in the incretin hormones glucagon-like peptide 1 and gastric inhibitory polypeptide, and their ability to stimulate additional insulin secretion. It has also been debated whether increased beta-cell mass may lead to excessive insulin secretion.

The article concentrated on the reaction to carbohydrates.

In Part 2 I will start to look at possible ways to compensate for this issue from a Low Carb diet perspective.

Part 2 continues here