Types of Diet
Types of diet, most of us have tried different diets from time to time. And for those familiar with social media, it is straightforward to hear claims that all kinds of diets are “the best.”
However, the simple truth is that there is no “best diet.”
Different diets suit different people, and trying to stick to an unenjoyable diet is a futile challenge that will eventually fail. Instead, a good diet should consider the individual’s unique likes and dislikes, beliefs, and much more. In the following, we will try to clarify the advantages and disadvantages of each of the above through different types of diets.
So, what different diets are there, and what are the potential pros and cons of each one?
Atkins diet
Atkins is a high-protein diet that achieved global popularity in the early 2000s.
It was the brainchild of a physician, Dr. Robert Atkins, and it is a low-carbohydrate, high-protein approach. But, unlike some low-carb diets, Atkins isn’t necessarily a high-fat diet.
While the approach has been controversial, many followers have claimed it is effective for weight loss.
Numerous clinical trials have examined the Atkins diet. A systematic literature review noted that nine out of ten short-term (<6 months) clinical trials demonstrated that the Atkins diet led to significant short-term weight loss. Over the longer term (>12 months), six out of eight tests found that participants effectively lose weight.
However, Atkins cuts a lot of perfectly healthy foods out of the diet. For example, according to ‘phase 1’ of the diet, only 20 grams of carbohydrates per day are “allowed.”
Thus, this strictly limits the intake of foods like fruit, vegetables, legumes, and whole grains. Nevertheless, nutritional research consistently finds these foods to have benefits.
DASH diet
The ‘Dietary Approaches to Stop Hypertension’ (DASH) diet is an eating pattern designed to help normalize blood pressure and prevent hypertension.
DASH has big backers, too, with the National Institutes of Health recommending it based on results from clinical trials. These studies found that the diet lowered blood pressure and improved the participants’ cholesterol (lipid) profile.
At its heart, DASH is a plant-rich, low-fat diet that emphasizes fruit and vegetables, grains, legumes, nuts, seeds, lean meat, low-fat dairy, poultry, and fish. It is also relatively low in salt, saturated fat, and sugar.
Systematic reviews and meta-analyses have demonstrated that DASH improves cardiovascular risk factors (cholesterol, blood pressure) and lowers the risk of all-cause and cause-specific mortality.
On the downside, these results are only possible if people successfully adhere to the diet, and only some do. In a systematic review of observational studies on DASH, there was a dose-response more excellent protection based on higher adherence. High and moderate adherence to the diet significantly lowered risk compared to low compliance.
This is why eating patterns should be tailored to the individual’s preferences; adhering to a diet you enjoy is much easier.
Example Meals
- Sweet potato, spinach
- Chicken curry, brown rice, peas, and carrots
- Grilled cod, wholewheat pasta, bell peppers, tomatoes
Ketogenic Diet
Ketogenic diets are a way of eating that strictly restricts carbohydrate intake, with the maximum level usually around 50 grams per day.
Unlike the carnivore diet, ketogenic (or ‘keto’ for short) diets can feature various animal and plant foods. These diets are often used for weight loss and to help control the symptoms of type 2 diabetes.
In this regard, clinical trials have shown mixed results on ketogenic diets. On the one hand, numerous randomized controlled trials have shown that ketogenic diets can lead to weight loss.
However, like any diet, successful adherence can be an issue with ketogenic diets. In a systematic review of thirteen randomized controlled trials, dropout rates ranged from 13% to 84%.
A further meta-analysis of twelve trials on ketogenic diets for intractable epilepsy demonstrated a combined adherence rate of 45%.
Understandably, restricting carbohydrate intake to such a low level is not the right fit for everybody. But ketogenic diets can be nutrient-rich if formulated correctly for those who enjoy the diet.
Example Meals
- Seafood and mixed vegetables cooked with cauliflower rice
- Roast chicken with spinach, mushrooms, and bell peppers
- Smoked salmon, lupin beans, avocado, and berries
Low-carbohydrate Diet
General low-carbohydrate (or ‘low-carb’) diets are much more relaxed than stricter versions like the ketogenic diet.
However, there is a distinct lack of standardized definition for a low-carb diet, so opinions will understandably vary. Randomized controlled trials have called anything up to 30% of calories from carbohydrates ‘low-carb.’
This carbohydrate would be equivalent to 150 grams daily on a standard 2000-calorie diet.
Interestingly, the American Academy of Family Physicians has attempted to define a low-carbohydrate diet. Their definition classes any diet with less than 20% of calories from carbohydrates as low-carb.
There are numerous interpretations of low-carb diets, ranging from healthful to somewhat questionable. That said, if formulated correctly, low-carb diets can be a perfectly nutritious way of eating.
On the positive side, a recent systematic review of systematic reviews provided clear evidence that low-carb diets can have beneficial effects for overweight and obesity. However, no good evidence supports low-carb above other weight-loss dietary approaches.
Some common concerns about low-carb diets include being low in fiber or excessively high in saturated fat, but neither has to be true. For instance, many sources of fiber can fit into a low-carb diet, such as berries, legumes, avocados, nuts, seeds, and more. Further, a low-carb diet doesn’t have to mean ‘high saturated fat.’
Example Meals
- Lambchop, sweet potato, grilled tomato, mushrooms
- Sardines with avocado, cheese, and salsa
- Tofu and root vegetable stew
Low-fat Diet
Low-fat diets are the complete opposite of low-carb, and they restrict fat intake to an upper limit of around 20-30% of calories. Based on a 2000-calorie diet, this equals approximately 45 to 66 grams of dietary fat per day.
By their very nature, low-fat diets tend to have a high carbohydrate content, emphasizing fruit, grains, legumes, and vegetables. Various randomized controlled trials have demonstrated that these diets can effectively lead to weight loss (if adhered to). However, they have roughly the same efficacy as low-carbohydrate diets in this regard, so personal preference is the decider.
One potential downside of low-fat diets is that fat intake can be taken too low. Dietary fat has numerous functions within the human body, and an adequate intake level is vital for the optimal absorption of fat-soluble vitamins. ‘Fat-soluble’ means that the nutrient doesn’t dissolve in water like some (such as vitamin C), and they need to be emulsified (and absorbed) with dietary fat. These fat-soluble vitamins include vitamins A, D, E, and K.
A clinical trial demonstrated an example of this fat-soluble vitamin absorption in action. In this study, 50 healthy older adults consumed vitamin D alongside a meal with either 30% of calories from fat or a fat-free meal. Those consuming the meal containing fat had a 32% higher peak plasma vitamin D level than those with the fat-free meal. In other words: it should be low-fat, but not no-fat.
Example Meals
- Whole Wheat toast topped with hummus, a piece of fruit
- Chicken breast, lentils, and vegetables
- Rice bowl with lean beef, vegetables, soy sauce, and seasonings
Mediterranean Diet
In truth, despite the name, there is no such thing as one ‘Mediterranean diet,’ and there are many diverse diets within the region.
However, the popular recognized meaning of ‘the Mediterranean diet’ is an eating pattern emphasizing fresh, whole foods. These foods include a high intake of fruits, legumes, nuts, olive oil, seeds, and vegetables and a moderate meat, poultry, and seafood intake. A reasonable amount of red wine may also be included if desired.
The diet is described as having soft eggs and sweet foods intake.
Most of the research on Mediterranean diets has focused on the above description for their formulation. Notably, the Mediterranean diet has more research than any other diet, and this research is positive.
To illustrate this, systematic reviews and meta-analyses analyzing observational studies and randomized controlled trials have suggested that diet may improve health markers like blood pressure and cholesterol levels. In addition, the diet may also lower the risk of cardiovascular and all-cause mortality.
Despite the potential health benefits of the diet, it doesn’t mean it is better than other dietary patterns for weight loss. On this note, a systematic review of Mediterranean diet interventions for long-term weight loss found that the diet was only equally as effective as low-carb, low-fat, and other comparator diets.
Once again, this shows that no ‘one diet’ is the right fit for all.
Example Meals
- Seafood stew with tomatoes, garlic, herbs, and seasonings
- Leafy green salad with tomatoes, red onions, feta cheese, olive oil, and seasonings
- Seasoned chicken with tahini and salad in wholegrain pitta bread
Paleo Diet
The paleo (or paleolithic) diet is a way of eating presumed to follow an ancestral eating pattern. In summary, the idea of the diet is that eating closer to how our ancestors ate throughout evolution would benefit the human body.
However, it is essential to note that people in the Paleolithic era had restricted food choices and a lack of knowledge of the nutritional effects of different foods. In other words, just because people used to eat in a particular way doesn’t necessarily mean it is the optimal way of eating now.
Additionally, it is worth noting that we don’t know exactly how people used to eat, and it likely depended on the specific time and locale. For example, some interpretations of the historical paleolithic diet suggest it was focused on animal foods, but others claim animal foods may have only played a small part.
That being said, the mainstream modern interpretation of the ‘paleo diet’ is a way of eating that includes fruits, vegetables, nuts, eggs, lean meat, and seafood. The diet also restricts dairy products, grains, legumes, and processed foods.
While the diet restricts an extensive range of foods, it is still possible to formulate healthy meals.
However, there is no real reason to restrict all the foods that paleo diets restrict, and dairy, legumes, and whole grains are all nutrient-rich foods that can fit into healthy dietary patterns.
What does the research show?
A systematic review of randomized controlled trials claimed that well-formulated diet versions might improve metabolic syndrome health markers. That said, this scientific paper had some questionable interpretations, and many of the results weren’t statistically significant, suggesting there may have been no effect at all.
Other research shows that paleo diets can lead to short-term weight loss, but there are question marks over whether this can be sustained long-term.
Example Meals
- Bell pepper stuffed with ground beef and vegetables
- Grilled mackerel with sauteed mushrooms and asparagus
- Stir-fried beef, mushrooms, onions, and peppers
Pescetarian Diet
Pescetarianism is a way of eating that excludes animal products except for seafood. Aside from this, it neither limits nor restricts any other type of food.
Put another way; the pescetarian diet is a vegan diet plus seafood.
Since seafood has most of the same nutrients as meat, this removes some of the nutrients of concern that would otherwise be present in a vegan diet. For example, fish is an excellent source of vitamin B12, which vegans would otherwise have to supplement, and also contains preformed omega-3s EPA and DHA.
One potential pescetarian diet is a vegan diet that includes bivalve shellfish (such as clams, mussels, and oysters), known as ‘ostro veganism.’ While controversial, some vegans feel these shellfish can fit into veganism as they are likely, not sentient.
Example Meals
- Grilled sardines, root vegetables, baked potato with hummus
- Rice and kidney beans cooked in coconut milk with vegetables
- Seafood chowder with potatoes and vegetables
Vegan (Plant-Based) diet
There is some confusion between the terms ‘vegan’ and ‘plant-based.’
Being vegan involves avoiding all animal products, whether food or clothing (such as leather shoes). In contrast, plant-based refers to foods and meals predominantly based on plants.
Plant-based diets are sometimes assumed to contain no animal products. This is mainly because ‘plant-based’ has become a marketing term for vegan diets.
However, plant-based diets can include animal products, and dietary organizations such as the American Dietetic Association refer to plant-exclusive diets as ‘vegan diets.’
Vegan diets restrict all animal products, including meat, poultry, seafood, eggs, and dairy. As a result, the diet requires either the supplementation of vitamin B12 or the inclusion of B12-fortified foods, as this nutrient is found exclusively in animal foods.
Other nutrients can be more challenging to obtain in sufficient quantities on vegan diets, including long-chain omega-3s (DHA/EPA), calcium, zinc, and vitamin D.
On the positive side, vegan diets focus on many whole-food plants such as fruits, vegetables, lentils, nuts, seeds, and whole grains. These foods are consistently associated with health benefits.
While long-term data on vegetarian diets exists, this needs to be improved for vegan diets. Short-term trials show that well-planned vegan diets may have various benefits, but it is unlikely they are solely due to the plant-exclusive aspect of the diet.
Example Meals
- Marinated tofu, lentil soup, vegetable side dish
- Lentil curry
- Pea protein guacamole with wholewheat toast
Vegetarian diet
Vegetarian diets restrict the consumption of all meat, poultry, and seafood. However, they can include animal agriculture products like cheese, eggs, and milk.
Nutritionally, vegetarian diets contain a broader range of foods than vegan diets and do not have the same nutrients of concern. One reason for this is that cheese, eggs, and milk are all rich sources of vitamin B12.
As a result, depending on the specific diet, vegetarians do not necessarily have to supplement vitamin B12 or consume B12-fortified foods.
Vegetarian diets have no long-term concerns; they may even offer benefits. For instance, a large observational trial that followed 96,469 people over roughly six years found that vegetarians had a 12% lower all-cause mortality risk.
However, it is tough to determine, but this may not be because of the diet’s vegetarian aspect (rather than the overall pattern).
Additionally, not all studies show the same outcome. For instance, a large Australian study that followed 267,180 people for six years found no difference in all-cause mortality between vegetarians and non-vegetarians.
Example Meals
- Cheese omelet with vegetables
- Marinated and baked tofu with stir-fried vegetables
- Feta cheese, cherry tomato, and olive salad
There is no perfect weight loss diet.
Different diets work for others; you should pick one that suits your lifestyle and tastes.
The best diet for you is the one that you can stick to in the long term.
What is the Best Diet For Me?
There are many different ways of eating, but the “best diet” depends on the individual.
Firstly, when determining what the proper diet might be for you, it is essential to place little emphasis on what has worked for others.
It can be tempting to give the latest popular diet a go or the one that is working for a friend or coworker. However, dieting is complicated, and it’s one of many nutrition myths that a particular diet will work for everyone.
For instance, it is possible to find a wide range of claims about how a particular diet “rescued” the health of somebody. This may very well be the case, but whether that diet is plant-based, DASH, ketogenic, or any other, it works for that person.
In other words, just because a way of eating is suitable for one individual does not mean it is equally the best choice for everyone. Nor does short-term health on a given diet predict longer-term health.
When considering a diet, it is essential to focus on:
- Including the foods you enjoy: an unenjoyable way of eating won’t be sustainable in the long term.
- Prioritize whole foods where possible: whole fruit > juice, potatoes > fried potato products, meat/poultry > processed meat products, and so on.
- Whether the diet suits our lifestyle: constantly busy? Eating six small meals a day won’t be the right fit. Endurance athlete? Regular food intake is essential.
- Encouraging satiety refers to satisfaction after eating and the subsequent lack of desire to eat more. Some foods promote satiety more than others, and focusing on these foods can help to control appetite and discourage excessive food intake. Foods that tend to be more satiating include protein and fiber-rich foods and foods with greater volume (such as whole potatoes). The satiety index of common foods is an excellent resource for help in this area.
- Ensuring recommended intake of essential nutrients: vitamin B12 supplementation is necessary for vegan diets, and vegetarian/vegan diets can make it harder to obtain sufficient DHA/EPA omega-3 and zinc. In contrast, diets lacking plant-based foods can make getting adequate magnesium, potassium, and vitamins C and E levels harder. Therefore, it is essential to be aware of the nutrients of concern for a particular diet or to work with a dietitian/nutritionist if this is difficult.
- How the diet affects our health: feeling terrible and constantly struggling to stick to a particular diet isn’t a good sign. Assessing how a specific diet makes us feel in this regard is essential. Also, it is always a sensible idea to have basic health checks after starting a new diet to ensure everything is as expected.
