Akins Diet

What is the Atkins diet?

The Atkins diet began in 1972 with the release of Robert C Atkins’ book ‘Dr Atkins’ diet revolution’ [1]. This book espoused the original tenets of the diet and gave guidelines – Atkins claims that carbohydrate intake is the main problem with American diets. Whilst this is not necessarily false, his belief was based on an incorrect reading of biology: he argued that there were metabolic advantages to eating fats because they required greater energy to digest. This was later declared false by actual scientific evidence [2], but Atkins’ influence had already spread and people were hooked on what came to be known as one of the first major ‘fad’ diets. This seems unfair, however: whilst Atkins’ original position was obviously-false and people tended to “yo-yo” diet with the Atkins diet, “low-carb, high-fat” diets (or LCHF) have been adopted by many individuals since and are definitely not fad diets.

Atkins’ diet relied on the reduction of dietary NET carbohydrates (dietary carbohydrates that aren’t fiber, which is essential for health [3]). The reduction of net carbs forces the body to rely more heavily on lipolysis – the consumption of fats (either dietary or stored) – for fuel. The end-goal of a low-carbohydrate diet is to enter ketosis: a stage where the body is relying almost solely on fat (mostly body fat) for its energy needs. This “lipo-adaptation” is widely recorded among individuals on “very low carbohydrate diets” and can be tested by a variety of scientific measures, but primarily through urine tests using ketosis sticks, which will change colour depending on the state of ketosis that an individual achieves.

The difficulty associated with the Atkins diet or any other form of LCHF diet is the time necessary to move from regular ketosis (a state that can generally be achieved in 1-3 days of a sufficiently low-carbohydrate diet) to genuine keto-adaptation or lippo-adaptation. This means that the body is not only compensating for low carbohydrates, as in the early stages of ketosis, but is preferentially using them. Some individuals believe that it can take as many as 2 years to make this long-term adaptation (especially in the western world where refined carbohydrates are a, if not the, primary food source), but the first stage has generally been ascribed to around 1 month of ketosis. The science ‘on the ground’ is sketchy for these claims, but they do not seem outrageous when we consider the adaptability of the human body to its surroundings.

Does it Work?

The big question around any diet is its efficacy: is it an effective way of dieting? Will it work? For how long? On what conditions? These are the important questions for anyone that might want to try the diet. As ever, the only universal response is it depends. The first thing to establish is that the Atkins/ketogenic diet is not a magical cure-all to the weight management problems of the world. It will have different effects on different individuals based on genetic predispositions and the way that they have dieted so far, as well as their body composition.

Obscuring Factors

Many people have had a great deal of success with the Atkins diet – otherwise we wouldn’t be publishing this review – but that does not mean that it is in any way superior to a variety of other diets. The first thing to consider with the effectiveness of Atkins, LCHF or keto diets is that they tend to work because diets in the English-speaking world are generally incredibly high in poor-quality, heavily-refined carbohydrates. In any society where there is an excessive consumption of a single food group, to the point of poor health, a diet that reduces that intake is likely to have positive effects in some way. The initial success of the Atkins diet should be qualified by the fact that any reduction in poor-quality foods will have health benefits, this need not set LCHF aside from a diet that focuses on, say, a smaller quantity of high-quality, whole carbohydrates.

Additionally, the makeup and digestion of carbohydrates and fats is generally quite different – this usually leads to incredible weight loss in the early stages followed by plateaus in the next stage. Carbohydrates tend to increase the body’s water retention, resulting in increased subcutaneous and transverse water weight [4], whereas fats generally do not. This means that an individual who is switching from a high-carbohydrate diet, rich in sodium and poor-quality grains, will likely lose a considerable amount of water weight ‘right off the bat’. This effect obscures a variety of results among LCHF studies and will give individuals incorrect estimations and expectations regarding their weight loss. Fat is generally bound to soluble fiber during the digestion process and removed from the body through excretion – it also has a soft limit on the quantity that can be absorbed at any one time: this means that a great number of the dietary fats we ingest will be excreted, reducing the overall calorie intake of an otherwise-eucaloric diet.

However, the most important singular factor in the effectiveness of the Atkins diet is the difference in calorie density between the foods promoted in the Atkins diet and the regular diet in English-speaking countries. Whilst fats may be the single most calorically-dense macronutrient at 9 calories per gram, foods which contain sugar or sugar-based syrups tend to have more calorically-active ingredients. This means that foods with high sugar content, for example, tend to have a higher calorie content because there are more macronutrients per 100g than in healthy fats. For example, in 100g of Avocado, there are approximately 170 calories [5], whereas in a chocolate bar of an equivalent weight there are anywhere between 200 and 400 calories. This is simply because the whole food contains less grams of digestible product and more fiber (which has no real caloric value). In this way, switching from refined carbohydrates to LCHF diets work by reducing the number of calories that we consume.

What does this all mean? Well, the scientific consensus on this issue is that ketogenic diets may work, but only because they affect short-term weight retention and, thereafter, reduce the amount of calories that we intake rather than due to ketosis itself. The question, once this has been established, is simple: why should choose Atkins’ diet over a calorie-controlled diet that focuses on high-quality sources and a balance of macronutrients?

In What Situations is Atkins Appropriate?

If we struggle to differentiate between the benefits of Atkins’ diet and a regular, macronutrient-balanced diet with good food sources (what Alan Aragon calls a “scientific diet”), then it is essential to establish when there might be benefits to individuals and look at the effects it has on health and performance. For example, individuals who struggle to break negative food-relationships with carbohydrates may make long-term habitual progress when they commit to a medium-term LCHF diet, improving long term health and weight management.

The individuals that require the greatest deal of carbohydrate-control are those who suffer from Type-II diabetes. In these individuals, an excessive consumption of carbohydrates may exacerbate the effects of an unstable blood sugar level, whereas foods which are high in protein, fat and fibre will have a relatively low-GI [6]. This will have positive effects on the stability of blood sugar, though reducing carbs too far may also be dangerous for these individuals. Anyone in this group should take extra care to consult a doctor prior to any serious dietary changes.

Some researchers, such as Jeff Volek, contend that there are serious advantages to athletes when they adopt a diet that encourages keto-adaptation [7]. The science for this is still mounting (for example, [8]), but it does not yet seem sufficient to outweight the “scientific” approach to dieting espoused by a great number of sports nutritionists and sport scientists. The measured approach appears to result from following a diet that is determined by the needs of the sport: for example, endurance athletes’ diets should focus on high quantities of intra-workout and inter-workout carbohydrates to ensure proper calorie intake relative to their output. We may say that athletes relying more heavily on faster energy systems (either ATP-CP or Anaerobic glycolysis) require less carbohydrates and may be better served by a diet that is relatively low-carbohydrate and high in fat, though the effectiveness of LCHF diets are almost exclusively restricted to low intensity exercises (again, see [8]). Whether or not we should advocate a thorough-going ketogenic diet has yet to be confirmed: longitudinal studies of ketogenic diets among experienced, elite athletes in strength and power sports are limited. Isolating variables among these individuals is almost impossible and controlling variables are even more difficult.

Practical Guidelines for Atkins/ketogenic Diets

The diet should focus on high-quality protein and fat sources, as well being very selective in terms of the sources for the carbs we do consume. We’ve broken this down into each of the main nutrient groups to give you an idea of some foods and approaches that make the diet easier and more effective.

Atkins’ diet generally proceeds through 4 major “phases” with different goals and different dietary recommendations.

  1. Induction – During the first stage, the body has to enter ketogenesis, this is achieved by radically cutting carbohydrates in the short term. For the first two weeks, we should be eating 20g of carbs or less (a “very low carbohydrate diet”, in scientific terms). This reduces the amount of carbohydrate-based water retention in the body and allows for some ketogenic adaptations.
  2. Balancing – This stage focuses on returning some small, high-quality carbohydrate sources to the body (some vegetables, nuts and seeds). This is intended to establish a low baseline for how much is sustainable over time.
  3. Fine-Tuning, or tweaking – As we approach a “goal weight”, carbohydrates are reintroduced to the diet in order to reduce the rate at which weight is lost. This allows us to achieve our goal weight and return to more sustainable eating habits.
  4. Maintenance – The Atkins diet did not originally aim at keto-adaptation like recent LCHF diets have, but rather used it as a short-term method for achieving a goal weight. When this goal weight has been achieved, we re-introduce carbohydrates slowly, only stopping when weight begins to increase again. Finding a balance of carbohydrates and proteins/fats is an essential part of maintaining weight after the Atkins diet, and will reduce the long-term worries about hunger in individuals who are on low-carbohydrate diets. Naturally, we should focus on high-quality carbohydrate sources.


Protein should be the centre of the Atkins diet, or any ketogenic diet: it is essential for tissue repair, fat loss and is very filling when compared to carbohydrates or fats. Protein should come from high-quality sources and should be the centrepiece of our meals. Some good protein choices are as follows:

  • Red meats (Beef, venison, kangaroo, elk, etc.)
  • Poultry (Chicken and turkey are great sources)
  • Fish – preferably fatty (Such as Salmon, Mackerel and Bass)
  • Eggs
  • Yoghurt
  • Cottage cheese

Luckily, these foods are incredibly versatile and can be cooked in many ways, with many accompaniments. These are the most important foods for performance in exercises, building muscle and losing fat. These should be included in every meal and can be incredibly delicious.


Fats should be the second largest component of the Atkins’ diet: this is where we get most of our calories from and should also be high-quality ingredients. The original Atkins diet included a huge quantity of animal fats: butter was one of the most controversial areas that Atkins originally promoted. We can’t really advocate for this, since even grass-fed butter is far from the best fat source. However, there are a number of good fats that provide huge amounts of energy and can be great for health and performance:

  • “Buttery” vegetables like Avocado
  • Olives
  • Fatty fish
  • Eggs
  • Steak and other fatty cuts of meat/poultry
  • Regular cheeses
  • Yoghurt
  • Nuts and seeds

Fats have a bad reputation because they include the word “fat” but the amount of fats you eat does not cause you to be fat. There are a huge number of good fats that can be included in a diet to replace the carbohydrates that we cut out.


The Atkins diet cuts out all starchy and sugary carbs, but it is still necessary to consume some carbohydrates, primarily because of the importance of dietary fiber. If we don’t consume fiber, the digestive system will basically shut down. Some of the high-fiber carbohydrate sources we might consider are:

  • Sweetcorn
  • Broccoli
  • Kale, Spinach and other leafy greens
  • Green beans
  • Watery veg like Lettuce and Cucumber

These sources should primarily be fibrous vegetables (not starchy ones) and not fruits (due to the high sugar content). They also contain a lot of the vitamins and minerals necessary for a healthy diet, which we might otherwise get from starchy foods.

What foods should we avoid or limit?

The Atkins diet focuses on the reduction of carbohydrates, so there are no prizes for guessing the main offenders that we need to watch out for:

  • Chocolate and sweets
  • Starchy baked goods (white bread, pasta, rice, pastries etc)
  • Grains (primarily wheat or anything derived from flour)
  • Sugary fruits (Oranges, apples and bananas, for example)
  • Starchy root vegetables (potatoes, sweet potatoes, parsnips) or yams
  • Legumes (like beans, chickpeas or lentils)
  • Anything that markets itself based on “low fat”
  • Poor quality meats (Pork, primarily, but also low-grade cuts)
  • Processed fats: anything high in trans-fats, hydrogenated fats or polysaturated fats

The quantity of these foods that we can consume depends on the phase that we are in and some of these are genuinely healthy foods when we consider them outside of the context of the Atkins diet. The inclusion of root vegetables (such as carrots or sweet potatoes), high-quality legumes or fibrous grains (primarily rolled oats) during later stages of the diet are important and should not be demonised. Despite arguments that the Atkins’ diet is a fad diet, the 4-stage process and the focus on high-quality food sources seems to suggest otherwise.

Closing remarks

Perhaps the most relevant question is should the general public use a ketogenic diet for weight loss and health? There are certainly some benefits such as the reduction of poor-quality carbohydrate intake, and a likely increase in vitamins and minerals from good-quality fat sources, but there are a number of nutrient-dense foods that would be cut out of the diet. For example, anyone who believes that legumes are all ‘unhealthy’ due to their carbohydrate content likely has a poor grasp of the essentials of nutritional science. Additionally, there are concerns that a low carbohydrate intake will negatively affect fat metabolism by reducing the availability of oxyloacetic acid, meaning that some carbohydrates are useful. There are aspects of the Atkins diet that should be considered when we look at the way that we all diet but, from the perspective of the average Joe or Jen, keto seems to be an unrealistic long-term solution with an excessively restrictive approach to carbohydrates. Reducing the quantity of carbohydrates (primarily refined), increasing the fiber intake and improving the source of our carbohydrates seems a more important and fruitful approach. Ketogenic diets, and Atkins in particular, tend to treat weight loss as a short-term problem: a diet is a long-term lifestyle change and should reflect a diet that we can maintain forever, effectively.

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[1] Atkins, R.C. (1972): ‘Dr Atkin’s diet revolution’. New York: Bantam
[2] The Lancet (2004), 364(9437), pp.897-899
[3] Anderson et al (2009): ‘Health benefits of dietary fiber’. Nutrition reviews, 67(4), pp.188-205
[4] Olsson and Saltin (1970): ‘Variation in total body water with muscle glycogen changes in man’. Acta physiologica Scandinavica, 80(1), pp.11-18
[5] USDA national nutrient database for standard reference release 28 [URL = https://ndb.nal.usda.gov/ndb/foods/show/2157 ]
Westman et al (2008): ‘The effect of a low-carbohydrate, ketogenic diet versus a low-glycemic index diet on glycemic control in type-2 diabetes mellitus’. Nutrition and metabolism, 5(36).
Yancy Jr. et al (2005): ‘A low-carbohydrate, ketogenic diet to treat type-2 diabetes’. Nutrition and metabolism, 2(34).
Dashti et al (2007): ‘Beneficial effects of a ketogenic diet in obese diabetic subjects’. Molecular and cellular biology, 302(1-2), pp. 249-256
Etc. ad nauseum
[7] Speaking at the NSCA Personal trainer conference, 2013 [URL = https://www.youtube.com/watch?v=ERXGCjxZTwM]
[8] Phinney et al (1983): ‘The human metabolic response to chronic ketosis without caloric restriction: preservation of submaximal exercise capability with reduced carbohydrate oxidation’. Metabolism, 32(8), pp.769-776