The Low-Carb High-Fat Diet?

Author: 

Kathy Pollard, MS

Question: 

Can you tell me why on earth does the low-carb, high-fat (LCHF) diet give such outstanding results and what are the long-term risks? It bugs me beyond belief that I have no answer.

One of the reasons is that I don’t understand how come diet based 70% on fat (mostly animal) consistently gives good results. How is this possible?

So far I have not seen a single study that compares WFPB and LCHF diets in terms of success rate for treating/reversing illnesses and weight management. Are there any? Can anyone of you explain the success stories of those who stick to the LCHF diet? Why is it so successful and the Atkins diet is not? Aren’t they really the same stuff but packaged differently?

Answer: 

Weight Loss on Low-Carb Diets

Low-carb diets give results for short-term weight loss compared to a standard American diet because any diet restricting calories will lower weight, and thus lowering carbohydrate and increasing fat and protein can induce weight loss, if the calorie count is lower. Further, depriving the body of its main source of fuel, carbohydrate, tricks it into breaking down other material for fuel, (first protein, then fat – more on that later).  First understand that the carbohydrate that most people consume in our society is refined carbs made up of simple sugars in foods bereft of fiber.

The Low-carb, high-fat (LCHF) diet is not much different from Atkins or any and all iterations of the low-carb, high-fat-and animal-protein diets as far as I can tell, though Atkins is a specific dietary regimen that requires control of carbohydrate intake without focusing on calories from fat, like traditional diets.  This could allow for burning fat reserves for fuel.  Other “low-carb” diets include Paleo, Ketogenic, Zone, South Beach, and anti-grain diets.  Most of these sprout from popular books, unfounded in the medical literature, and are largely similar.

Any diet that is an improvement over what is normally consumed, and/or lower in calories, will allow for weight loss.  A LCHF diet may give good short-term results in that area, but not in long-term health.  This does not give “outstanding results” from my view, as it adds health risks including impaired function of arteries,5 and puts a large burden on the liver.  Low-carb diets are also associated with higher all-cause mortality (higher death rates in general).1,2

Most folks opting for this LCHF form of diet are moving away from eating lots of refined foods that bombard the blood with simple sugars and demand a load of insulin, which can also lead to insulin resistance as well as weight gain.  If you cut those out, your insulin levels can stabilize.  It’s the refined carbohydrates that cause the problem, not carbohydrates in general!  Depriving the body of carbohydrate, its main source of fuel, hampers overall health in the long-run.  This is why losing weight with a high carbohydrate diet filled with whole plant foods containing fiber and complex carbohydrate that breaks down to simpler sugar slowly is a safe, health-promoting way to lose that weight, along with the bonus of improved health in the long-term.  The problem to begin with is that the typical diet most people consume is filled with added sugar and fat, (and excess protein) so the sugar provides the fuel and the fat provides the fat – fuel to store.

The Mechanism of Ketogenesis – Fat-Burning

Limiting carbohydrate deprives the body of it of its natural fuel and its short-term store of it in the form of glycogen.   Soon it must resort to breaking down muscle for protein.  Then it turns to breaking down fat, as it does in the state of starvation, to spare body protein, which is vital to life. Yay, now we’re breaking fat!  The body breaks down fatty acids for their substrate ketone bodies for energy and enters the state of ketosis.  But a ketonic state is supposed to be reserved for actual emergencies (read: starvation situations), keeping the body in stress and low in blood glucose. 3

Unfortunately eating this way will catch up with most people adding risk of any and all forms of cardiovascular disease, distressing the liver, heart, brain, prostate and sex organs.  Think of all that fat clogging arteries of every size, and going to organs, big and small. 

Along with the fat in any low-carb diet comes animal protein which adds risk for cancer and liver dysfunction. As well, there is increased hormone production, both growth and sex, stimulating cholesterol production and weight gain.  Even further, more animal protein comes with more heme iron, a powerful pro-oxidant damaging cells and causing inflammation which adds risk for all degenerative diseases, including cognitive degradation.4,5  And excess animal protein and fat contribute to kidney disease, hard to detect until late stages, but affecting 8% - 16% people worldwide. 5-7

The Blue Zones

The Blue Zones refer to the book by that name by Dan Buettner which reported on the most long-lived and healthiest communities in the world.  Buettner and National Geographic found pockets of these happy, healthy folks in Okinawa, Japan, Sardinia, Italy, and Loma Linda, California (Seventh Day Adventists), to name a few.  These folks were eating quite the opposite of the low-carb craze – local, mainly whole plant foods, filled with local greens, beans, starchy vegetables, along with small amounts of various animal foods.  This is probably how humans have eaten for hundreds of thousands of years. You can see the commonality of these populations in the diagram below.

Blue Zones Wikipedia Public Domain, https://en.wikipedia.org/w/index.php?curid=9630319

Eating this way naturally limits calories without limiting food intake, because whole plant foods have fiber, water and nutrients to fill us up and nourish our bodies.  It also protects our colon from nasty metabolites and pathogenic gut bacteria associated with atherosclerosis and cancers of the gut. 8,9 A LCHF diet cannot protect in this way.

In regard to your final thought, I would think it quite hard to do a comparative study of this LCHF diet with a WFPB diet, as the LCHF is hard to maintain long-term before health problems creep become apparent.  But there are lots of studies comparing various versions of vegetarian diets to meat-eating diets, all finding that the closer to a whole food, plant-based diet, the better health and longevity, with lower risk of all chronic diseases.  Here is a short list of some of those big studies, below, and a couple of short-term studies on the low-carb, high fat diet cited. (10,11).  These studies do show weight-loss, but also low adherence after a few months.10,11

I suggest doing a search of studies that you are interested in at plantbasedresearch.org, as new, relevant studies are coming out now more than ever!

 

References

  1. Johansson, I., Nilsson, L. M., Stegmayr, B., Boman, K., Hallmans, G., & Winkvist, A. (2012). Associations among 25-year trends in diet, cholesterol and BMI from 140,000 observations in men and women in Northern Sweden. Nutrition Journal, 11(1), 40. doi:10.1186/1475-2891-11-40
  2. Noto, H., Goto, A., Tsujimoto, T., & Noda, M. (2013). Low-carbohydrate diets and all-cause mortality: a systematic review and meta-analysis of observational studies. PLoS One, 8(1), e55030. doi:10.1371/journal.pone.0055030
  3. Gropper, Sareen S., Smith, Jack L., Groff, James L., Advanced Nutrition and Human Metabolism. Belmont: Wadsworth Publishing. 2005.
  4. Kell DB. Iron behaving badly: inappropriate iron chelation as a major contributor to the aetiology of vascular and other progressive inflammatory and degenerative diseases. BMC Medical Genomics. 2009;2:2. doi:10.1186/1755-8794-2-2.
  5. Moe, S. M., Zidehsarai, M. P., Chambers, M. A., Jackman, L. A., Radcliffe, J. S., Trevino, L. L., . . . Asplin, J. R. (2011). Vegetarian compared with meat dietary protein source and phosphorus homeostasis in chronic kidney disease. Clin J Am Soc Nephrol, 6(2), 257-264. doi:10.2215/cjn.05040610
  6. National Kidney Foundation. Global facts: about kidney disease. https://www.kidney.org/kidneydisease/global-facts-about-kidney-disease. 2016.
  7. Schwingshackl, L., & Hoffmann, G. (2013). Low-carbohydrate diets impair flow-mediated dilatation: evidence from a systematic review and meta-analysis. Br J Nutr, 110(5), 969-970. doi:10.1017/s000711451300216x
  8. Lombard KA, Olson AL, Nelson SE, Rebouche CJ. Carnitine status of lactoovovegetarians and strict vegetarian adults and children. Am J Clin Nutr. 1989;50(2):301-306.
  9. Flanagan, J. L., Simmons, P. A., Vehige, J., Willcox, M. D., & Garrett, Q. (2010). Role of carnitine in disease. Nutr Metab (Lond), 7, 30. doi:10.1186/1743-7075-7-30
  10. Samaha, F. F., Iqbal, N., Seshadri, P., Chicano, K. L., Daily, D. A., McGrory, J., . . . Stern, L. (2003). A low-carbohydrate as compared with a low-fat diet in severe obesity. N Engl J Med, 348(21), 2074-2081. doi:10.1056/NEJ
  11. Foster, G. D., Wyatt, H. R., Hill, J. O., McGuckin, B. G., Brill, C., Mohammed, B. S., . . . Klein, S. (2003). A randomized trial of a low-carbohydrate diet for obesity. N Engl J Med, 348(21), 2082-2090. doi:10.1056/N