With more than 1/3 of American adults having one form of cardiovascular disease with
Americans spending ~312.9 billion dollars annually on cardiovascular disease. This price makes it clear why diet and nutrition are such a debated subject. In fact, many people hop from one diet to the next more often than they shower…well maybe it isn’t that extreme, but you get my point.
Low-carbohydrate diets have become popular for weight loss over the past few decades, with research conflicted on its effect on weight loss and cardiovascular disease.
Recently, Bazzano (2014) split 146 men and women aged 22 – 75 years (mean age, 46.8 years; 88% female; 51% black) with a body mass index of 30 – 45 without cardiovascular disease, type 2 diabetes or kidney disease into two groups for 12 months:
- Low-carbohydrate Diet Group: Total carbohydrate minus total fiber of less than 40 g/d
- Low-fat Diet Group: Total energy from fat less than 30% (less than 7% from saturated fat) and 55% carbohydrate
“Participants were asked not to change their physical activity levels. Participants met with a dietitian in weekly individual counseling sessions for the first 4 weeks, followed by small group counseling sessions every other week for the next 5 months (a total of 10 sessions) and monthly for the last 6 months of the intervention (Bazzano 2014).”
Here are the results of the study:
Two 24-hour dietary recalls were obtained from participants at baseline and 3, 6, and 12 months for monitoring macronutrient intake.
Overall, total energy intake was similar between groups. The intake of carbohydrate was significantly higher and intakes of protein, saturated, and monosaturated fat were significantly lower in the low-fat group at 12 months.
Weight loss from baseline was greater in the low-carbohydrate group than the low-fat group
at 3, 6, and 12 months. The low carbohydrate diet also had a significantly greater reduction in fat mass and significantly greater lean mass at 12 months.
Waist circumference was reduced in both groups and not significantly different between groups at 12 months.
At 12 months, LDL (“bad cholesterol”) cholesterol had not significantly changed in either group. HDL (“good cholesterol”) increased significantly more in the low-carbohydrate group than the low fat group. Triglycerides decrease in both groups, with greater decreases in the low-carbohydrate group.
Blood Pressure and Glucose
The low-carbohydrate group had greater decreases in CRP. Blood pressure did not change significantly in either group, neither did plasma glucose. Insulin and creatinine decreased sgnificnatly in both groups.
Differences did not exist between black or white participants.
Summary on Low-Carbohydrate Diets
A major concern about low-carbohydrate diets is their potential to elevate LDL cholesterol levels, an established risk factor for CVD. In contrast, a recent meta-analysis showed that both low-fat and low-carbohydrate diets reduced LDL cholesterol levels, although the reduction was less for persons assigned to low-carbohydrate diets. This study also found reductions in LDL cholesterol level among participants in both groups, with no significant difference between the groups.
Self-reported dietary information may be subject to memory and recall issues, and participants who complete the dietary recall may be more likely to report adhering to the interventions. Luckily, the 24-hour recall was taken within one day of monitoring.
Also, the clinical tests for CVD were only a snapshot at time and don’t reflect the long-term effects (for decades of life).
Try a Low-Carb
If you are seeking weight loss or a reduction in cholesterol (LDL), consider a low-carbohydrate diet. Although we are not nutritionists, this long-term study is encouraging. If switching to a low-carbohydrate diet, keep these points in mind:
Within body composition devices most people vary 10%. Therefore, consistency is essential! Test yourself with the same device, at the same time, after the same meals. Best options, Bodpod, or DEXA. If neither of these options is available, bio-imedance home testing is adequate. If using scale also use the mirror test (look in the mirror: do you look better? Do you feel better? If yes to both, don’t question yourself and continue with the program!).
5 Tips for a Low-Carbohydrate Diet
Avoid “white” starchy carbohydrates (or those that can be white). This means no bread, pasta, rice, potatoes, or grains.
Eat the same few meals over and over again, especially for breakfast and lunch. You already do this; you’re just picking new default meals.
Don’t drink calories. Try to only drink plain coffee, tea, and water.
Only eat 10 grams of fruit (medium sized fruit) per meal. Generally speaking: Fructose → glycerol phosphate → more body fat. However, no human studies have found this association, making the biomechamistry slightly wrong. Likely due to the associated fiber in fruit.
Eat a lot of fiber! Cocoa is one high fiber food, but beans and lentils also do the trick.
Tips Moving Forward
If you are starting a diet for losing weight or improving your cholesterol, great job, this is often the hardest part! Just keep in mind, this is not a traditional diet, but something that you must work on for your entire life! Luckily, progress and improvement allows adaptation, but improvement and reaching your goals for improved health is first.
- Bazzano LA, Hu T, Reynolds K, Yao L, Bunol C, Liu Y, Chen CS, Klag MJ, Whelton PK, He J. Effects of low-carbohydrate and low-fat diets: a randomized trial. Ann Intern Med. 2014 Sep 2;161(5):309-18. doi: 10.7326/M14-0180.
Written by G. John Mullen, DPT, CSCS