Ketogenic Diets: The Silver Bullet for Weight-Loss?

Author: Christian Maino Vieytes, B.S. Nutritional Sciences, University of Maryland, College Park, M.S. Candidate, Division of Nutritional Sciences, University of Illinois at Urbana-Champaign

Keto is in! The newest low-carbohydrate craze is the magic pill that will rescue all of our weight-loss efforts! Or will it?

You may have heard about the ketogenic diet, or “keto” for short, over the past year. Don’t be fooled; the latest diet craze is nothing but a rebranding of the Atkins Diet, which was popularized by Robert Atkins in the 1970s. This fad diet is fixated on restricting an entire macronutrient category: carbohydrates (which by the way are the preferred fuel source for all of your body’s cells). The goal, of course, is weight-loss. It may seem harmless, but eating fewer carbohydrates means that you are, instead, eating exorbitant amounts of total fat, saturated fat, and protein.

The burning question: is it an effective method for short-term weight-loss?… Yes! But hold your horses, as we will look deeper into the science to see what it has to say on this “newest” diet.

So what led us here? Well, it turns out that ketogenic diets are incredibly effective for treating drug-resistant epilepsy. ^1,2 This has been a well-known and recognized treatment in the dietetic and medical community for quite some time. The evidence for using this diet in the general public is nowhere near as convincing.

Weight Loss

Why do Atkins, keto, and carbohydrate-restricting diets cause weight-loss? The answer is not as appealing as one may think. These diets are very effective at promoting weight loss in the short term (i.e., for no longer than three months). The primary way this occurs is by water-loss. When we restrict carbohydrates and eat a high-fat, high-protein diet, our body begins to deplete its glycogen stores, which are the carbohydrate reserves that muscle and liver cells keep handy in case of starvation (remember when I told you that carbs were the primary fuel source?). Water binds tightly to glycogen.³ As you start using up these glycogen stores for energy, the water is set free. The result? You’ve lost a lot of water weight without burning a lot of fat.

Repeatedly, studies have shown that weight-loss resulting from a ketogenic, low-carb diet is not sustainable. In these studies, weight loss was observed after 3-6 months, but the weight was regained after 12 months.^4–6 Moreover, weight loss appears to be more related to reduced calorie intake as opposed to the carbohydrate composition of the diet itself.^6–9

Your Health is More Important! 

Low-carb diets may come with a host of potential side-effects that include: kidney stones, constipation, fatigue, irritability, and headache. The long-term consequences are a bit scarier: elevated cholesterol, increased risk of cardiovascular disease and cancer, kidney disease, and even osteoporosis.^3,10,11 A landmark study, released earlier this year, reported that both very low carbohydrate consumption and high consumption patterns were associated with a greater risk of death from all causes, especially when the diet was made up of high amounts of animal protein and saturated fat that took the place of carbohydrates. ¹²

So what should we make of all these data? The focus should be on eating the right types of carbohydrates. Eating complex carbohydrates, primarily fiber and those found in fruits, vegetables, and whole grains has been associated with longevity and weight-loss.^13,14 Several studies have confirmed that eating vast amounts of these types of foods can help prevent cardiovascular disease, diabetes, and different cancers and promote better gastrointestinal health and function.^14–17 Consumption of carbohydrate from refined and processed sources should be kept to a minimum.

The Take Home Message

Don’t fear carbs! Just make sure to eat the right kinds from whole food sources. Ketogenic and carbohydrate-restricting diets may help us lose weight quickly in the short-term, but the long-term health consequences may not be worth it. Instead of embracing a dieting mentality and restricting and entire food-group, the focus should be on eating a varied diet with plenty of fruits, vegetables, whole grains, and adequate amounts of fat and protein. Not only is this beneficial for long-term longevity and for preventing chronic illness, but the science says it can help with weight management as a secondary effect.

References

1. Martin-McGill KJ, Jackson CF, Bresnahan R, Levy RG, Cooper PN. Ketogenic diets for drug-resistant epilepsy. Cochrane Database Syst Rev. 2018;11:CD001903. doi:10.1002/14651858.CD001903.pub4
2. Rezaei S, Abdurahman AA, Saghazadeh A, Badv RS, Mahmoudi M. Short-term and long-term efficacy of classical ketogenic diet and modified Atkins diet in children and adolescents with epilepsy: A systematic review and meta-analysis. Nutr Neurosci. October 2017:1-18. doi:10.1080/1028415X.2017.1387721
3. Astrup A, Meinert Larsen T, Harper A. Atkins and other low-carbohydrate diets: hoax or an effective tool for weight loss? Lancet. 2004;364(9437):897-899. doi:10.1016/S0140-6736(04)16986-9
4. Foster GD, Wyatt HR, Hill JO, et al. A randomized trial of a low-carbohydrate diet for obesity. N Engl J Med. 2003;348(21):2082-2090. doi:10.1056/NEJMoa022207
5. Brehm BJ, Seeley RJ, Daniels SR, D’Alessio DA. A randomized trial comparing a very low carbohydrate diet and a calorie-restricted low fat diet on body weight and cardiovascular risk factors in healthy women. J Clin Endocrinol Metab. 2003;88(4):1617-1623. doi:10.1210/jc.2002-021480
6. Stern L, Iqbal N, Seshadri P, et al. The effects of low-carbohydrate versus conventional weight loss diets in severely obese adults: one-year follow-up of a randomized trial. Ann Intern Med. 2004;140(10):778-785.
7. Bravata DM, Sanders L, Huang J, et al. Efficacy and safety of low-carbohydrate diets: a systematic review. JAMA. 2003;289(14):1837-1850. doi:10.1001/jama.289.14.1837
8. Foster GD, Wyatt HR, Hill JO, et al. Weight and metabolic outcomes after 2 years on a low-carbohydrate versus low-fat diet: a randomized trial. Ann Intern Med. 2010;153(3):147-157. doi:10.7326/0003-4819-153-3-201008030-00005
9. Lim SS, Noakes M, Keogh JB, Clifton PM. Long-term effects of a low carbohydrate, low fat or high unsaturated fat diet compared to a no-intervention control. Nutr Metab Cardiovasc Dis. 2010;20(8):599-607. doi:10.1016/j.numecd.2009.05.003
10. Larosa JC, Fry AG, Muesing R, Rosing DR. Effects of high-protein, low-carbohydrate dieting on plasma lipoproteins and body weight. J Am Diet Assoc. 1980;77(3):264-270.
11. Denke MA. Metabolic effects of high-protein, low-carbohydrate diets. Am J Cardiol. 2001;88(1):59-61.
12. Seidelmann SB, Claggett B, Cheng S, et al. Dietary carbohydrate intake and mortality: a prospective cohort study and meta-analysis. Lancet Public Health. 2018;3(9):e419-e428. doi:10.1016/S2468-2667(18)30135-X
13. Sylvetsky AC, Edelstein SL, Walford G, et al. A High-Carbohydrate, High-Fiber, Low-Fat Diet Results in Weight Loss among Adults at High Risk of Type 2 Diabetes. J Nutr. 2017;147(11):2060-2066. doi:10.3945/jn.117.252395
14. Liu L, Wang S, Liu J. Fiber consumption and all-cause, cardiovascular, and cancer mortalities: a systematic review and meta-analysis of cohort studies. Mol Nutr Food Res. 2015;59(1):139-146. doi:10.1002/mnfr.201400449
15. Reynolds A, Mann J, Cummings J, Winter N, Mete E, Te Morenga L. Carbohydrate quality and human health: a series of systematic reviews and meta-analyses. Lancet. 2019;393(10170):434-445. doi:10.1016/S0140-6736(18)31809-9
16. Dreher ML. Whole Fruits and Fruit Fiber Emerging Health Effects. Nutrients. 2018;10(12). doi:10.3390/nu10121833
17. Chan CW, Lee PH. Association between dietary fibre intake with cancer and all-cause mortality among 15 740 adults: the National Health and Nutrition Examination Survey III. J Hum Nutr Diet. 2016;29(5):633-642. doi:10.1111/jhn.12389