Sprache/Language: deutsch english

FAQ Ketogenic Diet


Frequently asked questions:

If you want to lose weight, is a reduction diet rich in fat better than a low-fat diet?

The key criterion for losing weight is having a negative energy balance. Low-carb, high-fat reduction diets replace almost all the carbohydrate energy with variable percentages fat and protein. Despite comparable energy deficits, low-carb reduction diets are usually easier complied with in the long run than low-fat, high-carbohydrate diet concepts (ALHASSAN et al. 2008). Characteristic features of low-carb diets are that you will get a better and longer-lasting feeling of satiety after meals, a more stable blood sugar level, and a lesser or even absent feeling of hunger (GIBSON et al. 2015, BODEN et al. 2005, MCCLERNON et al. 2007, NICKOLS-RICHARDSON et al. 2005). These effects are also obtainable by a low daily intake of carbohydrates (approx. 30 g), i.e. when you eat low-carb foods having a low glycemic index. Such a diet still permits eating foods like vegetables or low-carb nuts known to have characteristic micronutrient profiles. A one-sided micronutrient supply will be prevented this way, and you must not do without secondary plant substances and fiber substances. In addition, the body will be able to better mobilize its fat reserves on account of the absent insulin peak, which is due to a ketogenic nutrition, and the changed hormonal conditions will exert a protective action on the muscles which in turn will have a positive impact on the basal metabolic rate.
In fact, it can be said that in most cases low-carb reduction diets are more successful than the low-fat variants in producing a weight loss (BAZZANO et al. 2014, FOSTER et al. 2003, LIEBMAN 2014, NICKOLS-RICHARDSON et al. 2005, SAMAHA et al. 2003, BUENO et al. 2013) and the non-fat substance will be better retained as well (CAPPELLO et al. 2012, KRIEGER et al. 2006, VOLEK et al. 2002).

I want to use the ketogenic diet as a way to lose weight. Must I practise sport in order to succeed with my diet?

No. The ketogenic weight-loss diet can also work perfectly well without carrying out any sporting activities. Only the negative energy balance is crucial. However, through sport you can increase your energy requirements and as a result create a negative energy balance more easily. In this regard the author recommends that you take regular exercise anyway. Look for something that you enjoy. If you do not find anything then at least go for regular walks. This is the most natural form of movement for people and also keeps your circulation moving.

Is a diet consisting of 65-80 % fat healthy? What does such a diet do when it's applied over a longer period or on a permanent basis?

A diet rich in fat under a concomitant carbohydrate deprivation (no insulin peaks) will in principle not cause a problem. On the contrary, a ketogenic diet can improve your blood values (e.g. lower the triglycerides, increase the "good" cholesterol, decrease the "bad" cholesterol, etc.) (STERN et al. 2004, DASHTI et al. 2006). However, the quality of the fats and the distribution of the fatty acids also have an important part to play. A high percentage of n-6 fatty acids, hardened vegetable fat, and so-called trans-fatty acids should be avoided. Sensitive fats should not be exposed to too much heat. A long-term or permanent ketogenic diet is estimated to be safe (HUSSAIN et al. 2012, DASHTI et al. 2006).
If you are not sure whether you can take this kind of diet for health reasons, ask your doctor and have your blood values checked, preferentially before you change your dietary habits and afterwards in regular intervals (e.g. 2-3 months after diet change and then annually). Based on the results of your blood tests, you and your doctor will be able to decide on how to further proceed. If your doctor disapproves of your ketogenic diet without stating comprehensible reasons for his opinion, show him some of the published studies or consult another doctor. There are only rare instances in which a ketogenic diet really must not be applied (for example, serious metabolic disorders).

Concerning the distribution of fatty acids, it is recommended consuming monounsaturated fatty acids for the most part and keeping the polyunsaturated fatty acids low. Why is that so and how can I put that into practice?

In general, we distinguish saturated fatty acids (SFAs), monounsaturated fatty acids, (MUFAs) and polyunsaturated fatty acids (PUFAs). Concerning the right distribution of fatty acids, I recommend consuming MUFAs, SFAs, and PUFAs in amounts of a decreasing order.

First of all, the more unsaturated a fatty acid (depending on number of chemical double bonds in a molecule), the more susceptible it will be to destructive oxidation processes. PUFAs contain two or more of these double bonds, for which reason a limitation of the absolute intake applies to this group of fatty acids. However, we still have to supply our bodies with certain PUFAs on a regular basis because two of them are nutrients which are essential to humans (alpha-linolenic acid and linoleic acid). The ratio between n-3 and n-6 fatty acids should not be shifted too much in favor of the n-6 fatty acids. As compared with the PUFAs, monounsaturated fatty acids are less susceptible to oxidation, and SFAs display almost no oxidation behavior at all.
Furthermore, we may take some scientific studies and evaluations on this subject into consideration. As far as the human health impact of various macronutrients and fatty acid distributions is concerned, the study evaluations made by MENSINK and KATAN (1992) already revealed that there will be a decrease in triglyceride values if carbohydrates are substituted by fat, and an improvement of the HDL/LDL ratio if the saturated fatty acids are substituted by PUFAs or MUFAs. In their regression analysis of earlier publications YU et al. (1995) were able to demonstrate that an increased intake of MUFAs produced an increase of HDL cholesterol levels ("good" cholesterol) and a decrease of LDL cholesterol levels ("bad" cholesterol). And MENSINK et al. (2003) were able to determine a reduction of the ration between total cholesterol and HDL cholesterol if typical fat sources used by Americans were substituted by canola oil, soybean oil, or olive oil. In their meta-analysis, SCHWINGSHACKL et al. (2011) referred to the blood-pressure-lowering effects of MUFAs in adipose test subjects. SCHWINGSHACKL and HOFFMANN (2012) underscored in their evaluation of the current study situation the potential for the application and recommendation of MUFAs, previously less examined than the PUFAs, not least because - apart from the positive effects of this class of fatty acids on various health markers - no detrimental effects resulting from the application of MUFA-rich diets have ever been published in the literature.
What significance does this have to someone who is on a ketogenic diet? The percentage of fat in a ketogenic diet is distinctly higher than in most studies which have investigated the effects of the distribution of fatty acids. The positive effects of the unfortunately also oxidation-prone PUFAs described in the literature should come to bear, even despite their lower percentage (albeit comparable absolute amounts). According to the opinion of the authors, potential negative effects on the body are to be expected less from the group of the MUFAs (as compared with the other groups of fatty acids), even if they are supplied in relatively high absolute amounts, for which reason MUFAs should constitute the major proportion. The recommendable intake of saturated fatty acids would finally rank between PUFAs and MUFAs. You should take this into consideration when you chose the right fat source, apart from avoiding hardened vegetable fats and trans-fatty acids and despite the generally positive study situation regarding the influence of ketogenic diet (even irrespective of the origin of the fats, the fatty acid distribution or the quantities of protein supplied).

Concerning realization:
According to my recommendations, a ketogenic diet shall comprise both animal fats (meat and other animal-derived foods, butter, other animal fats) and vegetable fats (nuts, vegetable oils). Most animal fats are composed of monounsaturated and unsaturated fatty acids, each contributing to almost 50 percent, and low amounts of polyunsaturated acids. In vegetable fats and oils, the distribution of fatty acids may vary depending on the plant source or origin, however, the percentage of PUFAs will most often be very high. In order to keep the oxidation potential on a low level, you should particularly avoid vegetable oils rich in n-6-fatty acids and instead rely on vegetable oils containing a high percentage of MUFAs (most of all olive oil). Saturated fatty acids won't present any problem, however, they are already taken up with animal food products. PUFAs which should be consumed only in small amounts are already taken up with nuts, fatty fish etc., depending on the food you chose, and they are even present in considerable amounts in vegetable oils containing a high percentage of MUFAs. If you regularly eat products derived from animal sources which are rich in fat you should rather consume, as a tendency, more vegetable oils containing a high percentage of monounsaturated fatty acids, hence olive oil. If the percentage of animal fat in your diet is lower you can use proportionately more coconut oil and/or coconut fat which consists almost entirely of saturated fatty acids. However, it may be stated at this point that high-fat food derived from animal sources is expressly recommended.
As already mentioned earlier, the requirement of the two essential fatty acids, i.e. alpha-linolenic acid and linoleic acid, must be satisfied despite any limitation on PUFA uptake, in particular that of the n-6 fatty acids. Both essential fatty acids are contained, for example, in canola oil (00-canola) which is additionally relative rich in MUFAs.
You can look up the exact distributions of the fatty acids contained in foods and foodstuffs in good nutrition value tables when you do your own research (You will find help on this topic in the chapter dealing with Nutrient Management).

I have done without carbohydrates for several days and according to the test strips I have recently reached a state of ketosis. Regrettably, I feel totally de-energized. Is that a normal condition? Is it going to stay that way?

After reaching a state of ketosis your metabolism still needs some time until it will be capable of utilizing the fatty acids to the full extent and thus make enough energy available to you. Your tissues still depend too much on the energy source glucose. Your initial lack of energy and drive is quite normal in fact (VINING et al. 1998, LEFEVRE and ARONSON 2000). Be a little bit patient and persevere, you will feel much better in a few weeks (BRINKWORTH et al. 2009, YANCY et al. 2009).

I hardly engage in sports at all. Is the protein powder good for me?

In the ketogenic diet described here, the maximum carbohydrate uptake rate for most users will be at 30 g/d. The protein supply should not exceed 1.5 to 2.0 g/kg body weight (relative to one's theoretical normal weight). The rest is fat. Hence it follows that low-fat foods do not make much sense. One example: If a woman with a theoretical normal weight of 55 kg consumes 1,500 kcal during a ketogenic reduction diet she will derive

The challenge of this diet is to keep your relative fat intake high enough. You can work with protein powder excellently in this regard, by supplementing it together with fats or oils. For example as a shake or with peanut butter. With that you can easily "conceal" a high fat content.

Why do I have to check my intake of vitamins and minerals? I haven't done that before and it seems to be somewhat laborious to me.

Changing to a ketogenic diet requires that you make comprehensive rearrangements of your choice of foods. Your carbohydrate intake must be stopped almost completely, and you must know the carbohydrate content of every food and beverage you eat or drink. Even a minor or one-time exceedance of your maximum carbohydrate allowance will be capable of preventing the state of ketosis. In order to be on the safe side, particularly beginners most often start with a small selection of foods. But even routine dieters have to cancel whole groups of foods with characteristic micronutrient profiles from their diet sheets and, in case of a reduction diet, there will be also an altogether lower food intake. All this harbors the risk that users might underprovide themselves with single micronutrients.
I therefore recommend that the supply of nutrient and minerals should be subject to a coarse revision every now and then. Unnecessary dietary mistakes can be avoided this way and deficiency states easily prevented because, even in a ketogenic diet, it is not difficult to supply yourself with all the essential nutrients you need as a human being. Furthermore, it is extremely useful for you to occupy yourself a little bit with the nutrient contents of food you eat. This way you will rapidly acquire a good notion of their (micro)nutrient profiles. However, an exact calculation of each and every micronutrient will not be necessary.

I would like to use the ketogenic diet to lose weight. After making good progress initially my weight has now been stagnating for several weeks. I would like to lose some more weight, according to the ketosis test strip I am now in a state of ketosis. What could I have done wrong?

If we still have energy packed on our stomachs and hips, if we are in state of ketosis and our energy balance is negative, then body fat will melt away. This happens in every one of us and it is exactly what evolution always meant to happen with body fat. Under exactly these conditions our metabolism will initially care less that that enough food is actually available. After a longer period of ketogenic nutrition (weeks to months or years), however, the plateau problem might become a topic of concern despite the ketosis maintained, because your energy balance might possibly no longer be negative after some time. In connection with ketogenic diets it is often claimed that you do not have to bother about calories anymore. This is a risky business because the energy balance must be negative for the reduction of body fat, and this also applies to a ketogenic reduction diet. What often happens is this: By changing from a carbohydrate-rich to a ketogenic diet, hence to a diet rich in proteins and especially fats, your choice of foods will also change. At the beginning, the result for many people is that they become satiated sooner (unusually high fat and protein contents) and start to eat less. Their energy deficit is "accidentally" negative, even without having to control their calorie intakes, and the people lose body fat. Although hunger should not be of any significance in ketosis (exception: a strong appetite in cases of certain types of nutrient deficiencies), one's adaptation to the "new" food could result in an increased food intake, perhaps even until the energy deficit has been compensated for, and weight loss will begin to stagnate. For this reason, the energy input should be roughly calculated again and your energy deficit ascertained, at least in the event of an unwanted stagnation of weight loss. If the energy deficit returns, fat will burn again. With a little exercise, this will be quite easy to do and you will automatically get a better subjective feeling for the energy contents of the food you eat. So don't waste your time by not controlling your energy input!

I want to use the ketogenic diet as a permanent diet (not as a weight-loss diet). Must I still count my calories?

If you tend to gain weight you should at least pay serious attention to your energy balance. If you have already followed my guidelines and lost weight you will know your energy requirements by now. In practice you do not then need to recalculate them for every meal. Prepare some standard meals with a known energy content for yourself. Some of them below half of your daily energy needs, some above half. Since you only need to eat two meals, you can then combine the meals according to the desired trend without losing sight of your objectives. That quickly becomes a routine!

List of references:

Alhassan S, Kim S, Bersamin A, King AC, Gardner CD: Dietary adherence and weight loss success among overweight women: results from the A TO Z weight loss study. International Journal of Obesity 2008; 32(6): 985-991; PMID: 18268511

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. Annals of Internal Medicine 2014; 161(5): 309-318; PMID: 25178568

Boden G, Sargrad K, Homko C, Mozzoli M, Stein TP: Effect of a low-carbohydrate diet on appetite, blood glucose levels, and insulin resistance in obese patients with type 2 diabetes. Annals of Internal Medicine 2005; 142(6): 403-411; PMID: 15767618

Brinkworth GD, Noakes M, Clifton PM, Buckley JD: Effects of a low carbohydrate weight loss diet on exercise capacity and tolerance in obese subjects. Obesity 2009; 17(10): 1916-1923; PMID: 19373224

Bueno NB, De Melo IS, De Oliveira SL, Da Rocha Ataide T: Very-low-carbohydrate ketogenic diet v. Low-fat diet for long-term weight loss: A meta-analysis of randomised controlled trials. British Journal of Nutrition 2013; 110(7): 1178-1187; PMID: 23651522

Cappello G, Franceschelli A, Cappello A, De Luca P: Weight loss and body composition changes following three sequential cycles of ketogenic enteral nutrition. Journal of Research in Medical Sciences 2012; 17(12): 1114–1118; PMID: 23853627

Dashti HM, Al-Zaid NS, Mathew TC, Al-Mousawi M, Talib H, Asfar SK, Behbahani AI: Long term effects of ketogenic diet in obese subjects with high cholesterol level. Molecular and Cellular Biochemistry 2006; 286(1-2): 1-9; PMID: 16652223

Gibson AA, Seimon RV, Lee CM, Ayre J, Franklin J, Markovic TP, Caterson ID, Sainsbury A: Do ketogenic diets really suppress appetite? A systematic review and meta-analysis. Obesity Reviews 2015; 16(1): 64-76; PMID: 25402637

Foster GD, Wyatt HR, Hill JO, McGuckin BG, Brill C, Mohammed BS, Szapary PO, Rader DJ, Edman JS, Klein S: A randomized trial of a low-carbohydrate diet for obesity. The New England Journal of Medicine 2003; 348(21): 2082-2090; PMID: 12761365

Hussain TA, Mathew TC, Dashti AA, Asfar S, Al-Zaid N, Dashti HM: Effect of low-calorie versus low-carbohydrate ketogenic diet in type 2 diabetes. Nutrition 2012; 28(10): 1016-1021; PMID: 22673594

Krieger JW, Sitren HS, Daniels MJ, Langkamp-Henken B: Effects of variation in protein and carbohydrate intake on body mass and composition during energy restriction: A meta regression. The American Journal of Clinical Nutrition 2006; 83(2): 260-274; PMID: 16469983

Lefevre F, Aronson N: Ketogenic diet for the treatment of refractory epilepsy in children: A systematic review of efficacy. Pediatrics 2000; 105(4): E46; PMID: 10742367

Liebman M: When and why carbohydrate restriction can be a viable option. Nutrition 2014; 30(7-8): 748-754; PMID: 24984988

McClernon FJ, Yancy WS, Jr, Eberstein JA, Atkins RC, Westman EC: The effects of a low-carbohydrate ketogenic diet and a low-fat diet on mood, hunger, and other self-reported symptoms. Obesity 2007; 15(1): 182-187; PMID: 17228046

Mensink RP, Katan MB: Effect of dietary fatty acids on serum lipids and lipoproteins. A meta-analysis of 27 trials. Arteriosclerosis; Arteriosclerosis and Thrombosis 1992; 12(8): 911-919; PMID: 1386252

Mensink RP, Zock PL, Kester AD, Katan MB: Effects of dietary fatty acids and carbohydrates on the ratio of serum total to HDL cholesterol and on serum lipids and apolipoproteins: A meta-analysis of 60 controlled trials. The American Journal of Clinical Nutrition 2003; 77(5): 1146-1155; PMID: 12716665

Nickols-Richardson SM, Coleman MD, Volpe JJ, Hosig KW: Perceived hunger is lower and weight loss is greater in overweight premenopausal women consuming a low-carbohydrate/high-protein vs high-carbohydrate/low-fat diet. Journal of the American Dietetic Association 2005; 105(1): 1433-1437; PMID: 16129086

Samaha FF, Iqbal N, Seshadri P, Chicano KL, Daily DA, McGrory J, Williams T, Williams M, Gracely EJ, Stern L: A low-carbohydrate as compared with a low-fat diet in severe obesity. The New England Journal of Medicine 2003; 348(21): 2074–2081; PMID: 12761364

Schwingshackl L, Strasser B, Hoffmann G: Effects of monounsaturated fatty acids on cardiovascular risk factors: A systematic review and meta-analysis. Annals of Nutrition and Metabolism 2011; 59(2-4): 176–186; PMID: 22142965

Schwingshackl L and Hoffmann G: Monounsaturated Fatty Acids and Risk of Cardiovascular Disease: Synopsis of the Evidence Available from Systematic Reviews and Meta-Analyses. Nutrients 2012; 4(12): 1989-2007; PMID: 23363996

Stern L, Iqbal N, Seshadri P, Chicano KL, Daily DA, McGrory J, Williams M, Gracely EJ, Samaha FF: The effects of low-carbohydrate versus conventional weight loss diets in severely obese adults: One-year follow-up of a randomized trial. Annals of Internal Medicine 2004; 140(10): 778–785: PMID: 15148064

Vining EP, Freeman JM, Ballaban-Gil K, Camfield CS, Camfield PR, Holmes GL, Shinnar S, Shuman R, Trevathan E, Wheless JW: A multicenter study of the efficacy of the ketogenic diet. Archives of Neurology 1998; 55(11): 1433-1437; PMID: 9823827

Volek JS, Sharman MJ, Love DM, Avery NG, Gómez AL, Scheett TP, Kraemer WJ: Body composition and hormonal responses to a carbohydrate-restricted diet. Metabolism 2002; 51(7): 864-870; PMID: 12077732

Yancy WS Jr, Almirall D, Maciejewski ML, Kolotkin RL, McDuffie JR, Westman EC: Effects of two weight-loss diets on health-related quality of life. Quality of Life Research 2009; 18(3): 281-289; PMID: 19212822

Yu S, Derr J, Etherton TD, Kris-Etherton PM: Plasma cholesterol-predictive equations demonstrate that stearic acid is neutral and monounsaturated fatty acids are hypocholesterolemic. The American Journal of Clinical Nutrition 1995; 61(5): 1129–1139; PMID: 7733039

Forget what's EASY. Do what's RIGHT.
Legal Notice - Data Privacy Statement