The Atkins Diet – Will Cutting Out Carbohydrates Help You Lose Weight?

The most famous diet book of all time, named “Dr Atkins New Diet Revolution” by cardiologist Robert Atkins, was the start of a low-carbohydrate diet trend that still remains today.

Diets such as the Paleo or Ketogenic diet can even be argued to be ‘spin-offs’ of the original Atkins diet, that was first published in 1972.

Despite the name of the book, the proposed message was that the Atkins diet was not simply a ‘diet’ but rather a lifetime nutritional philosophy.

The books immense popularity was obvious, as people were envious of the idea that they could become in shape and healthy while consuming their favorite foods (meat and dairy) and eliminating their worst foods (fruits and vegetables).

Not to mention that the book claimed that as long as you stuck to the rules of the plan, you could eat unlimited quantities of the ‘approved foods’.

Interestingly, the original Atkins book was modified by Robert Atkins in 2002 based on major criticism from nutritionists and dietitians regarding the very high protein intake, along with the lack of vegetables and dietary fiber.

This brought along the ‘modified Atkins diet’ which now recommends a slightly lower protein intake that provides a similar amount of calories to dietary fat, however the very low carbohydrate content remains.

The dietary fat intake is also suggested on the modified diet to come mainly from unsaturated fats from plant sources, as opposed to saturated and trans fats from animal products; more of a push towards plant oils, nuts, and avocados.

The modified Atkins diet is now seen as a first step before progressing to a strict ketogenic diet protocol – very high fat, moderate protein – that can be beneficial in outpatient settings.

How Does The Atkins Diet Work?

The program is broken up into four different phases that the dieter will complete consecutively; we’ve broken them down below:

Phase 1

Almost all carbohydrates are cut from the program, consuming ~20 grams of carbohydrates a day, mainly from vegetables. It is mentioned to focus on “foundation” vegetables, such as asparagus, broccoli, celery, cucumber, green beans and peppers. All meals should include an animal-based protein source; fish, shellfish, poultry, meat, eggs, and cheese. This phase should last for at least two weeks, depending on weight loss goals.

Phase 2

A continued intake of ~20 grams of carbohydrates per day made up of “foundation” vegetables. However, small amounts of nutrient-rich carbohydrates, such as more vegetables and berries, nuts, and seeds, can be included as weight loss continues.

Phase 3

Start to gradually increase the range of foods you eat, including fruits, starchy vegetables and whole grains by ~10 grams of carbohydrates per week as long as weight loss continues.

Phase 4

When a goal weight has been reached, some flexibility to carbohydrate intake is allowed but in general a low-carbohydrate diet should still be continued to allow for maintenance of results.

What Is The Reasoning Behind The Diet?

The main claims from the Atkins diet are weight loss, maintenance of weight loss without hunger, good health, and disease prevention.

Further than this, the Atkins’ diet proposes weight reduction without conscious caloric restriction.

Advocates of the Atkins diet state that carbohydrates are the main cause of most health issues in the world and are the reason for the current obesity epidemic. Hence the Atkins diet focuses on the elimination of carbohydrates from the program.

Like the Ketogenic diet, the Atkins diet is also now used to treat patients with epilepsy due to its apparent neurological benefits.

Is This A Good Diet For Weight Loss?

The Atkins Diet claims that those on the program can lose 15 pounds in the first two weeks – although it acknowledges results aren’t typical.

The Atkins diet tends to cause weight loss in most individuals due to a significantly reduced caloric intake.

Although research on the Atkins diet specifically is scarce, the average caloric reduction is approximately 1000 calories per day, equating to an approximate 40% reduction from habitual caloric intakes.

A longitudinal study showed that the Atkins diet causes between a 4-5% weight reduction within the first month [1]. However, results vary depending on an individual’s calorie intake and activity levels.

Despite the Atkins diets claims that weight loss is caused by a reduction in carbohydrates, the results can be fully explained by the unsolicited decrease in calorie intake and water weight.

More to this point, the Atkins diet results in an unanticipated initial water weight loss of 2-4lbs that is common in low-carbohydrate diets, due to lowered glycogen (stored carbohydrates) content and ketosis-induced diuresis; increased delivery of sodium to the kidney by ketones inducing water loss [2].

It should be noted that water weight lost from low carbohydrate intake should not be confused with fat loss, and this weight will be regained when carbohydrates are reintroduced to the regime.

The Atkins Diet Potential Health Benefits

Other than its ability to help followers lose weight, there’s a whole host of other beneficial aspects to the Atkins diet. Below we’ve listed the health benefits that have been proven in scientific studies:

Increased Protein Intake

Proteins are large, complex molecules that are critical for cellular function, and are required for the structure, function, and regulation of the body’s tissues and organs.

An increased protein intake is associated with increased levels of satiety due to its effect on ‘hunger hormones’ such as ghrelin and leptin, as well as effecting sensory and cognitive signals.

Compared to the other macronutrients, protein also has a higher rate of thermogenesis – the amount of calories required in order to digest and absorb an ingested nutrient – thus increasing the level of energy expenditure.

For these reasons, a high protein intake is effective at reducing overall energy intake in individuals that are not tracking their daily ingested calories. This is important for those with a goal to make simple changes to aid weight loss, and benefit from the health improvements that come with this – improved blood lipid profile, inflammation, glucose control etc.

Interestingly, studies have even found that when calories from dietary fat are the same, high protein intakes produce more weight loss compared to moderate protein intakes [3]. The satiating effect of protein likely dramatically reduces carbohydrate intake, and thus overall caloric intake.

Another positive that comes with an increased protein intake is the stimulatory effect the nutrient has upon muscle anabolism and protein synthesis. This will favor the retention of lean muscle mass during dieting phases, and result in an improved body composition that positively impacts on health biomarkers such as insulin sensitivity; the uptake of glucose to cells when insulin is spiked.

Although it is speculated in the media that high protein intakes can damage health, data shows no effect on blood lipids, or harm to kidney and liver function [4].

Reduced Insulin & Blood Sugar Levels

As carbohydrates are the main cause of elevated insulin and blood glucose levels, a restriction or elimination of their intake can lead to less fluctuations in their production which may benefit health and mood.

For these reasons, the Atkins diets may have a more significant impact on those suffering with diabetes and insulin resistance who need specialized control and care for insulin and blood sugar levels.

In fact, it has been shown that low-carbohydrate diets may reduce the necessary insulin doses (injected) in diabetics by ~50% within the first few weeks [5].

However, individuals who use blood sugar medication should always consult with a doctor before making dramatic changes to carbohydrate intake, as a vastly reduced carbohydrate intakes may result in hypoglycaemia (insufficient blood sugar levels).

The Atkins Diet Drawbacks

While the diet seems to be on the whole positive, there are some drawbacks that we believe should be noted:

The Diet Introduces The Potential For Blood Lipid Imbalances

Current data suggests that the Atkins diet may cause an increased risk of hyperlipidaemia (abnormally high amounts of cholesterol and fatty acids in the blood) which may lead to cardiovascular and cerebrovascular (brain) complications.

Even though such a low-carbohydrate diet commonly leads to weight loss, which usually improves health irrelevant of diet composition, the Atkins diet has resulted in significantly increased LDL-cholesterol and total cholesterol after 3 months [6].

This is a worrying sign for any diet as weight loss would typically improve blood lipid profiles irrelevant of diet quality. To the same point, if lipid profiles are worsening during times of weight loss, then they will likely be worsened further on an Atkins diet that is not energy-restricted.

However, it is noted that in individuals that continue the program for at least a year, blood lipid values seem to at least begin to normalize and there is a trend for HDL (“good” cholesterol) to rise and partially compensate for the negative effects of LDL.

This can be viewed as a long-term metabolic adaptation to poor cardiovascular health which could reduce the progression rate of vascular dysfunction on the Atkins diet, although this is yet to be confirmed.

To add to this, while most evidence from carbohydrate-restricted diets shows a beneficial shift from ‘small’ LDL-cholesterol particles to ‘large’ LDL-cholesterol particles, the Atkins diet seems to create the reverse effect – increased ‘small’ LDL particles.

This is a key finding, as ‘small’ LDL-cholesterol particles cross the arterial wall very easily and promote vascular cell dysfunction, often leading to atherogenesis; formation of plaques around the arteries [7]. Notably, the increased concentration of ‘small’ LDL-cholesterol appears to cause dyslipidaemia (elevated fatty acids and cholesterol in the blood) and premature coronary artery disease.

Following Atkins May Lead To Nutrient Deficiencies

Diets that revolve around the restriction of certain food groups inevitably increase the risk of nutrient deficiencies as the availability of certain nutrients is reduced.

In general, low carbohydrate diets decrease consumption of fruits, vegetables and whole grain products. In turn, this consistently seems to reduce the overall intake of dietary fibre, vitamins, calcium, potassium, magnesium, iron, as well as other bioactive compounds and phytochemicals.

On the Atkins diet specifically, dietary deficiencies are seen with vitamin A, vitamin B6, folate, vitamin C, magnesium, iron, calcium, potassium, and fiber [1].

As expected, nutrient deficiencies in any of these substances can cause both minor or major side effects, dependent on the extent of deficiency. In extreme cases, major deficiencies that are not dealt with can lead to disease and even death.

Unless an individual tracks their nutrient intake while on an Atkins diet to ensure they have sufficient intakes of each essential micronutrient, it is advised to avoid such a restricted program.

This being said, as individuals progress through the phases on the ‘modified’ Atkins diet, the restriction of food groups becomes less severe and may reduce the chances of micronutrient deficiencies.

The Diet Promotes An Excessive Intake of Animal Products

Another alarming issue with the Atkins diet is the large amount of animal products that will inevitably be included given the restrictions to other food groups.

Although animal products can be part of a balanced diet, their consumption in excess undoubtedly causes issue, specifically regarding heart disease, aging, and potentially certain cancers.

The main issues with large meat consumption are the high saturated fat and cholesterol intakes that come attached to these products.

In particular, saturated fat has the ability to raise blood cholesterol by reducing the number of LDL-cholesterol receptors and increasing the rate of both LDL-cholesterol oxidation, both of which cause inflammation and arterial plaque formation.

In the same manner, excess dietary cholesterol may be responsible for cholesterol crystal-induced arterial wall injury and leads to increased inflammation, plaque build-up and subsequently the onset of atherosclerosis [8].

As well as these two negative impactors on health, the high methionine content in meat may increase free radical generation, and the rate of oxidation leading to protein damage and age acceleration.

In addition, methionine can react with glucose to create gaseous sulphur-containing compounds which may increase tumor proliferation rates, and is associated with cancer progression [9].

Meat mutagens, such as heterocyclic amines, and the high amount of heme iron within meat also have a carcinogenic nature such as promoting neoplasia; abnormal tissue growth [10].


The Atkins diet was the first popularized low carbohydrate diet that focuses on high-protein, high fat, and a very low carbohydrate intake.

It is advertised to induce weight loss, maintain weight loss without hunger, improve health, and prevent disease.

The program tends to cause weight loss due for most individuals due to a significantly reduced caloric intake.

However, relative to more balanced diets, Atkins seems to have a negative influence on blood lipid profiles, and the increases in LDL-cholesterol may increase heart disease risk.

The large amounts of animal products consumed on such a diet may also lead to excessive saturated fat and dietary cholesterol intakes that may be responsible for increasing inflammation and progressing arterial plaque build-up.

Due to the restrictive nature of the program, it can also lead to micronutrient deficiencies that can cause many side effects and be a notable safety concern.