One of the things TheFatNurse has noticed about eating a reduced carb and high fat lifestyle is the drop in blood pressure TheFatNurse is experiencing. Seriously, TheFatNurse has gone from an average of 124/75ish to…110/62…what the hell…time to look into this mofo.
This is an older study in the Arch of Intern Med from 2010 that is pretty interesting (1). It compared a low carb diet to a low fat diet + Orlistat. This drug works by preventing the absorption of fat and therefore reduce calories. Of course if you ain’t absorbing it…it’s gotta come out somewhere right? Thus, one of the potential “treatment effects” is fat oily and foul smelling stools known as steatorrhea.
The researchers were looking to see what sort of metabolic, body weight and adverse effects these two diets would have in a 48 week period in overweight subjects with some having obesity related problems such as diabetes, lipid issues and hypertension. However, despite the low fat diet having a leg up with medication versus the low fat diet, the researchers still predicted the low carb diet would make participants lose more weight.
One of the things TheFatNurse always checks when experiments are testing low carb diets is what they mean by “low carb.”. Depending on who’s doing the study, low carb can be defined anywhere from 10 to 40 percent of one’s daily caloric intake. Even a 40% carb diet can technically be classified as low carb since the USDA Dietary Guideline For Americans actually recommends upwards of 65% of your daily diet being from carbs. The diets in this study seemed to reflect the more hardcore low carb community diet:
Participants were instructed to restrict carbohydrate intake initially to less than 20 g/d using pocket guides and hand- outs. Participants could eat unlimited meat and eggs, 112 g of hard cheese, 0.48 L of low-carbohydrate vegetables (eg, leafy greens), and 0.24 L of moderate-carbohydrate veg- etables (eg, broccoli, asparagus) daily; calorie intake was not restricted.
And the low-fat diet with orlistat:
Participants were instructed to restrict intake of total fat (<30% of daily energy), saturated fat (<10% of daily energy), cholesterol (<300 mg daily), and calories using pocket guides, hand- outs, and individualized goals.13,14 Recommended calorie in- take was 500 to 1000 kcal below a participant’s calculated weight maintenance intake.15 In addition, a 30-day supply of orlistat (120 mg before meals 3 times a day) was provided monthly.
Notice something? The low-carb diet had no restriction in calories but the low fat diet followed the usual protocol of eating below your maintenance caloric intake (along with the usual less than 10% saturated daily fat and less than 300 mg daily cholesterol. So what were the results?
Despite the different diets, both groups lost similar weight with no statistical differences. Additionally, triglycerides, LDL-C, HDL-C improved in both groups with no statistical differences either (remember tho, the LDL/HDL cholesterol isn’t the true benchmark, its the particles but no lipoprotein particle testing was done here). Additionally, TheFatNurse thought the Hemoglobin A1c1% change was pretty interesting. A1C1 measures your sugar levels for the past 3 months and in this study the percent of change was -0.30 (CI; -0.52 to -0.09) for the low carb diet compared to the -0.06 (CI; -0.36 to +0.14) for the low fat diet with orlistat. That’s a pretty good change, although it wasn’t statistically significant (P=0.10); This means there’s a 10% probability that the differences were due to chance. Just an interesting observation.
Perhaps the most interesting portion was the Blood pressure readings. The low carb diet won out with a difference of (in mm Hg) -7.44 (CI;-11.12 to -3.75) systolic and -4.97 (CI;-7.64 to -2.29) diastolic. with P values for both <.001. People eating the low fat diet with Orlistat actually increased their blood pressure on average.
When one thinks about the diet composition of the low carb group with the results its pretty interesting. Remember the instructions, “eat unlimited meat and eggs.” This translated to the low carb group eating not only more calories in general, but almost double the amount of total fat on a daily basis. As for saturated fat? The low carb group ate a little bit more than double the saturated fat on average daily than the low fat group. Cholesterol intake? Well over double on average compared to the low fat group.
Contrast that with what’s in TheFatNurse’s review textbook that TheFatNurse used for the nursing licensure exam on reducing hypertension:
“Consume a diet low in fat, saturated fat, and cholesterol.”
Hmm…quite the opposite results we got in this study? So why is this? Well the lower carbohydrates consumed will effect the body’s insulin levels. insulin has an effect on the kidneys. It causes your kidneys to retain salt and therefore lead to increased blood pressure. Is this new to you? TheFatNurse thinks it might be for a lot of people, but it shouldn’t be considering “the sodium-retaining effects of insulin have been known for a long time [since 1953].” (2)
Bottomline: TheFatNurse is not against low fat per se, just against the stigma that fat has gotten in today’s society. Additionally, please don’t make the mistake of treating this study as a low fat vs low carb high fat diet (LCHF) fight because the inclusion of orlistat makes true comparisons difficult. Not to mention this is just one study. TheFatNurse used this study to show results can run contrary to what is taught about eating fat and changes inside the body.
Other News: Yes TheFatNurse is updating at a snails pace so far lol. Lots of changes going on right now with TheFatNurse, will hopefully start posting more regularly once things settle down
1) William S. Yancy Jr, MD, MHS; Eric C. Westman, MD, MHS; Jennifer R. McDuffie, PhD, RD, MPH; Steven C. Grambow, PhD; Amy S. Jeffreys, MStat; Jamiyla Bolton, MS; Allison Chalecki, RD; Eugene Z. Oddone, MD, MHS (2010). A Randomized Trial of a Low-Carbohydrate Diet vs Orlistat Plus a Low-Fat Diet for Weight Loss. Arch of Intern Med. 170(2) 136-145
2) B. Grunfeld, M. Gimenez, M. Balzaretti, L. Rabinovich, M. Romo, and R. Simsolo (1995) Insulin Effect on Renal Sodium Reabsorption in Adolescent Offspring of Essential Hypertensive Parents. Hypertension 26 1089-1092.