Diet Plans – Everything You Need to know

Last updated January 11th 2016

Diet plans are an integral part of a weight loss programme. There is a great variety of different diet plans available, some of which will be more beneficial for certain groups of people than others.

Following a healthy diet plan is thought to be key to losing weight. There are a great many different diet plans available, not all of which will work for everybody.

It is important for dieters to understand the way in which a certain plan is thought to help with weight loss and whether or not it will be suitable for their health and lifestyle.

A selection of the most common diet plans will be discussed in this article, as well as clinical studies on different types of diet. You will learn which dietary supplements to use alongside which diet plans, and how to work out which type of diet plan might be best for you.

What are Diet Plans?

A diet plan provides a way of controlling what food you put into your body. Diet plans are usually utilised to aid weight loss (though they can be used for other health reasons, or even to aid weight gain) and often come with a set of rules that the user must follow. They vary in detail greatly; some plans will involve a few defined rules that should change your eating habits, whilst others will have a very limited set of foods that can be eaten. Some diet plans will come with set meal ideas and recipes that should be followed daily, whilst others will involve more research and planning by the user themselves.

It is important to take into consideration your health, lifestyle and goals when searching for a suitable diet plan. Some diet plans are designed to be followed alongside regular exercise, and some might not be suitable for diabetics, for example. Similarly, crash diets might help people to lose weight in the short-term, but if you are looking for a long-term reduction in body weight, then you will need to find a plan that is designed as such, to help you to incorporate long-term changes into your lifestyle.

Why are Diet Plans Important?

In 2013, 67% of men and 57% of women were classed as overweight or obese in England. The proportion of obese adults has increased significantly over the past decade or so and is putting pressure on the National Health Service. Being overweight has an array of adverse effects on an individual’s general health, ranging from an increased risk of cardiovascular problems to suffering from type 2 diabetes and gallstones. For those who are overweight, losing weight can therefore have substantial benefits for general health and wellness.

Making dietary changes is incredibly important if you are looking to lose weight. In order to lose weight, an individual must expend more calories than they consume. As such, weight loss typically involves a combination of reducing calorie intake and increasing energy expenditure through exercise. Diet plans are not typically focussed just on reducing the amount of food that a person eats, but rather making long-term changes to eating habits and encouraging a diet of healthier foods that will be beneficial for the body’s general health. Often, diet plans will encourage the consumption of fruit and vegetables and discourage snacking on processed and sugary foods.

The Most Common Diet Plans

Choosing a diet plan can be a daunting task; a number of factors need to be taken into consideration and there are a great many diet plans available to choose between. Whilst it is possible to create your own diet plan by cutting out fatty foods and increasing the amount of fruit, veg, and lean meat that you consume, many people choose to follow a pre-made diet plan with a strict set of rules to follow. Below, we will briefly describe some of the most common diet plans. For a greater insight into the different diet plans available, see the NHS page on the topic.

The Atkins Diet

The Atkins Diet is based principally on the idea of increasing fat burning by cutting out all carbohydrates from your meals. At the beginning of the diet, carbohydrate intake is strictly restricted to just 20g; as the weeks pass however, the amount of carbohydrates that you are allowed to consume increases to a point that you think you can maintain in the long run.

The original Atkins diet plan was criticised for severely limiting the foods that you were allowed to eat; the New Atkins diet however allows for a more nutritionally balanced diet to be consumed. Whilst cutting out carbs might have its benefits, some have stated that the Atkins diet might not be healthy, as consumers will still be eating saturated fats, which might have adverse effects on health.

The Paleo Diet

The Paleo diet has gained a lot of attention in the past few years, with a number of different books being published on the topic. This diet plan is based on the hypothesis that our bodies are not well adapted to consume the processed foods that make up a lot of peoples’ meals in the western world today. It is argued that in order to get the most from our diet for our overall health, we should revert to the foods that were consumed in the Palaeolithic era, before the agricultural revolution.

The diet is high in protein and foods such as fruit, vegetables, nuts, seeds, meat, and seafood. These are all foods that could be hunted or gathered in the wild. Foods that are forbidden include wheat, grains, dairy products, potatoes, and refined sugar. This diet is open slightly to interpretation, with some people suggesting much stricter rules than others. There is no specific list of rules, and even if they were, it would be open to criticism since the exact diet of our Palaeolithic ancestors is not fully understood.

The 5:2 Diet

In contrast to the previous two diets, the 5:2 diet plan is based on a principal known as intermittent fasting. This diet does not restrict the food groups that the consumer can eat, but instead severely restricts the amount that they can eat on two days of the week. People who follow the 5:2 diet eat and drink as they please for five days of the week, but must then restrict their caloric intake severely, to just 500 or 600, for their chosen two days of the week.

Proponents of this diet plan advocate that it is easier to stick to than diets that involve daily calorie restriction or those that involve severely limiting certain food groups. Critics however argue that fasting is not a safe way to lose weight and might have adverse health effects. Once again, users would also not typically cut out ‘unhealthy’ foods such as fatty and sugary items.

The Slimming World Diet

Slimming World is a club that people looking to lose weight can join; the club offers group meetings and provides members with meal plans, advice, and motivation to lose weight, for a fee. The Slimming World diet plan works on a ‘points’ scheme and aims to educate users on how to live a healthily lifestyle as well as helping them to lose weight in the short-term.

No food groups are completely banned and treats are allowed. There are also ‘free foods’ that you can eat as much of as you like; these include fruits, vegetables, potatoes, lean meat, fish, and rice. Slimming World aims to offer gradual weight loss that can be maintained. Some people find that joining a weight loss group such as Slimming World helps to keep them on track with their diet, though some argue that Slimming World does not help to prepare consumers for weight maintenance after you cancel your membership to the club.

Clinical Studies on Diet Plans

Whilst specific diet plans have not often been subject to rigorous clinical testing, scientific studies have been performed on certain types of diets, such as those that involve cutting out certain food groups. A clinical study is a trial that is performed by scientists in the case of diet plans to determine whether or not a method is safe and effective. They will usually involve a group of volunteers, half of which will follow the diet plan in question whilst the other half will be used as a control. It is said that different diet plans work for different people, but clinical studies should offer the best insight into whether or not a diet plan is likely to be effective more generally.

Clinical Studies on Low-Carb Diets

Diets that involve restricting carbohydrate intake have been subject to significant study in the past, particularly in trials comparing the potential benefits of low-carb diets with those of low-fat diets.

Authors of a meta-analysis published in 2006 searched the literature for relevant clinical studies that compared the impacts of low-fat diets with low-carb diets on weight loss and associated factors. Five trials were identified that fitted their inclusion criteria, using a combined sample of 447 participants. The results of statistical analyses on the pooled data from all of the studies indicated that for the first year, low-carb, non-energy restricted diets were as effective as low-fat, energy-restricted diets for weight loss. It was noted however that low-carb diets caused beneficial changes in triglyceride and HDL cholesterol levels, but adverse changes on LDL cholesterol levels.

One study compared the effects of a low-carbohydrate diet with those of a low-fat diet in severely obese patients. 132 subjects took part in the trial, which continued for six months. The results indicated that a low-carb diet could be more beneficial for weight loss than a calorie- and fat-restricted diet. A second study produced similar results; this trial involved 63 obese subjects and continued for one year. It was reported that individuals on the low-carb diet lost more weight than those on the conventional diet for the first six months, but at the one-year point, the differences did not remain significant. Improvement in some risk factors for cardiovascular problems was noted for those in the low-carb diet group.

A review study published in 2002 looked at the potential effects of very-low carbohydrate diets and addressed a selection of potential concerns associated with this kind of diet. For example, it has been suggested that low-carb diets could lead to insulin resistance. The authors of this paper state that data do not support the hypothesis that low-carb diets increase the risk of an individual contracting type 2 diabetes and that they might in fact be beneficial to glucose control. For many years there has also been an association between high-carb diets and endurance exercise; the effects of low-carb diets on exercise performance are not fully understood, but some studies have shown no detrimental effect and others have even reported improved performance in endurance exercise.

Clinical Studies on Intermittent Fasting Diets

Intermittent fasting, or intermittent very low-calorie, diets have also been subject to clinical study, though perhaps not to the same extent as low-carb diets. Results of trials have generally indicated that intermittent fasting can be beneficial for weight loss in normal and diabetic subjects.

A 2011 study utilised as sample of 107 overweight or obese women to test the effects of intermittent continuous energy restriction against those of continuous energy restriction. The trial was randomised and continued for six months, during which time a selection of measurements were taken. The results of this study suggested that intermittent energy restricted diets are as effective as continuous energy restricted diets in terms of weight loss, insulin sensitivity, and cholesterol levels. Intermittent energy restricted diets might also be beneficial for reducing the risk of disease.

Another study was performed to investigate the effects of intermittent very low-calorie diets on individuals with type 2 diabetes. The 54 overweight subjects were randomly assigned to a behavioural therapy group or to a very low-calorie diet group, with either intermittent therapy for one day a week for 15 weeks, or for five consecutive days every five weeks. Individuals in both of the very low-calorie diet groups were seen to lose more weight than those in the behavioural therapy group by 20 weeks. No significant changes were reported in fasting plasma glucose levels, but improvements in HbA1c were notable in the intermittent five-day very low-calorie diet subjects.

Review papers have also been published on the topic. One such paper compared the effects of daily calorie restriction (reducing energy intake every day) to intermittent calorie restriction (24 hours of unrestricted energy intake followed by 24 hours of complete or partial food restriction, repeated). The authors state that both diets are effective for weight loss, but which might be better is not yet confirmed. Results of the analysis indicated that 12 weeks of the diets both cause similar levels of weight loss and fat mass loss, but that intermittent calorie restricted diets might be more beneficial for the maintenance of lean body mass.

Diet Plans and Dietary Supplements

Dietary supplements are, as the name suggests, designed to supplement a healthy diet and regular exercise in order to bring about their desired effect – in this case, weight loss. It is very important to remember that a supplement advertised as a weight loss aid will not have a significant effect if taken with the same diet and lifestyle that you have been following previously. In order to make the most of a supplement, it is recommended that you choose a healthy diet plan to follow too, and couple this with an exercise programme.

Whether you choose to find a supplement to compliment your diet plan or a diet plan to compliment your choice of supplement, it is important that you take a few things into consideration. Dietary supplements can generally be divided into six categories – fat burners, appetite suppressants, metabolism boosters, carbohydrate blockers, protein shakes, and those that target a combination of the aforementioned areas of weight loss.

There are some combinations that would be quite logical; for example, taking an appetite-suppressing supplement might help the user to stick to a portion-controlled diet. Fat burners and metabolism boosters might be suitable for any type of diet, although it has been suggested that these products would work better when taken alongside regular exercise.

Similarly, protein shakes are only likely to be beneficial for body composition if the protein is used to make muscle mass; in order for this to happen, the user must be undertaking regular exercise. Finally, it should be noted that carbohydrate-blocking supplements would be of little use to individuals who have opted for a diet plan that significantly restricts carbohydrate consumption, such as the Atkins diet or the Paleo diet.

These are not the only factors that need to be taken into consideration when choosing a weight loss supplement or diet plan. Of equal importance is finding one that is suitable for your health and lifestyle. Some metabolism boosting supplements, for example, are not suitable for individuals who have a history of cardiovascular disease. Some diet pills are also not recommended for those who have diabetes, or a gastro-intestinal condition. For more information on how to choose a dietary supplement that suits you, see our guide to choosing the best diet pill.


Which Diet Plan will be best for you?

With so many options available, how do you decide which type of diet plan will be best for you? There are several questions that you can ask yourself in order to narrow down your options. Firstly, do you think that paying to join a club and having access to advice and support will help to keep you on track? If so, then a group such as Slimming World, Weightwatchers, or LighterLife might be useful for you. Secondly, are you willing to cut large food groups from your diet, such as carbohydrates? If not, then the Atkins diet and Paleo diet would not be your best options.

Thirdly, are you going to be undertaking a significant exercise regime alongside your diet? The 5:2 diet would have to be fitted carefully around any exercise programme – it would not be recommended that you perform exercise on a ‘fasting’ day. The type of exercise must also be taken into consideration; if you are looking to take up regular long-distance running or swimming, then it might not be beneficial to cut out carbohydrates from your diet as they are an important source of energy for endurance exercise. If you are looking to join the gym and perform resistance exercise however, then protein might be considered to be more important to your diet.

It is also worth thinking about what you want to get from your diet; some will be more useful in terms of educating you about how to eat healthily in the long-run than others. Some will also be easier to follow, with, for example, the option to purchase pre-made dinners (e.g. the SlimFast Diet). It might be beneficial for other users to take their health into consideration when choosing a diet; some diets for example, are designed specifically for those who have a heightened risk of suffering from cardiovascular problems (e.g. The South Beach Diet). The Paleo Diet has also been suggested to help to reduce your risk of cancer and diabetes, amongst other health conditions; whether or not these claims hold any truth is debateable.


There are a number of factors that should be taken into consideration before deciding on a diet plan. These include your health, your lifestyle, and your eating habits. It is important to remember that there is not one single diet plan that will best suit everybody. Diets that a low in fat and those that are low in carbohydrates have been shown to be beneficial for weight loss in clinical studies, as have intermittent fasting diets. It is recommended that you choose a diet plan that is suited to your eating habits and that you combine the plan with regular exercise.