Flexitarian Diet Book

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What Is The Flexitarian Diet?

The flexitarian diet describes a lifestyle where an individual actively looks to reduce their meat consumption, but is not strictly a vegetarian. For lack of a better term, it could also be described as a ‘semi-vegetarian’ diet that occasionally includes meat or fish.

There are no rules or guidelines when it comes to the flexitarian diet, and therefore the amount you need to reduce meat consumption to become a ‘flexitarian’ is subjective. However, most people on the diet choose to restrict meat intake to around 1-3 times per week.

This diet is as a result of a popular stance that we should be reducing our meat intake, whether this is for health, ethical, or environmental reasons.

It can even be viewed as a stepping stone for those wanting to become a vegetarian or vegan, if someone would like a more gradual transition to such a lifestyle.

Recent surveys indicate that 1/3rd of people in modern societies have reduced their meat consumption in the last 12 months.

For many, this stems from the latest reports that long-term consumption of red meat, particularly processed meat, may increase the risk of mortality, cardiovascular disease, type 2 diabetes, and certain forms of cancer such as colon cancer [1].

The International Agency for Research on Cancer has also now classified red meat as “probably carcinogenic”, and processed meat as “carcinogenic” to humans [2].

Foods to Eat on the Flexitarian Diet

To ensure a well-balanced flexitarian diet make sure to regularly consume:

  • Legumes: Beans, lentils, chickpeas.
  • Vegetables: Kale, spinach, green beans, carrots.
  • Starches: Potatoes, squash, oats, quinoa.
  • Fruits: Berries, oranges, bananas.
  • Nuts: Almonds, walnuts, cashews
  • Seeds: Flaxseeds, chia seeds.

When incorporating animal products, choose the following when possible:

  • Poultry: Organic, free-range.
  • Fish: Wild-caught.
  • Dairy: Organic from grass-fed animals.

Tip to Help Reduce Meat Intake

When switching meat to plant-sources, be sure to replace the meat portion of the meal with another food that is also high in protein and has a similar texture.

An adequate serving of either beans, lentils, nuts, chickpeas, or soy will fit this recommendation nicely.

For palatability purposes, it may be beneficial (at least initially) to experiment with meat substitute products such as meatless ‘chicken breast’, quorn mince, vegan burgers etc. This may make the transition easier as dietary changes seem less drastic.

The Health Benefits (Science-Backed)

Although research has highlighted the benefits of a plant-based diet, the degree to which this research applies to a flexitarian diet is unknown. This becomes even more difficult considering there is no definition of a Flexitarian diet and what it includes.

Nevertheless, research on vegan and vegetarian diets are still able to give some indication into the potential benefits for promoting better health.

May Assist Weight Loss

It has been shown that, on average, people who follow a plant-based diet lose more weight than people on an omnivorous diet [3].

Specifically, a large review found that those following a vegetarian diet for ~4 months lost 4.5lbs more than those who did not [4].

Vegans, who remove all animal-based products, are also the only dietary group that have an average healthy body mass index (<25 kg/m2), and the body mass index of other dietary groups actually increases accordingly with the frequency of meat intake per week [5].

The main reason for this effect is because it is common for people who reduce meat intake to swap this for plant-based foods, which are generally lower in calories and thus contribute to a reduction in daily energy intake.

May Increase Longevity

Current estimates are that global mortality will decrease 6-10% if people transitioned towards a more plant-based style of eating that aligned with standard dietary guidelines [6]

Associations have also been found between higher intakes of red and processed meat, and increases in risk for total mortality, mainly from cancer and cardiovascular disease [7].

The extent that reducing meat intake will affect somebody on an individual basis cannot be predicted, and will be vary depending on genetic predispositions, such as the efficiency of an individual’s fat and cholesterol metabolism.

Reduced Inflammation

Fruit and vegetables, fundamental to a plant-based diet, are inversely associated with the level of inflammation in the body [8].

It is thought that the increased intake of dietary fiber on such a diet has the ability to modulate the intestinal microbiome and its metabolites, that are significant contributors to the amount of systemic and local inflammation [9].

In particular, soluble fiber interacts directly with gut microbes and produces metabolites such as short-chain fatty acids that leads to healthier microbial communities within the digestive tract.

Bioactive compounds occurring in plant foods, primarily carotenoids and flavonoids, can also influence immunological processes.

There is also emerging evidence that semi-vegetarian diets could be an option for patients with irritable bowel disease, such as Crohn’s disease, that stem from chronic inflammation in the gut [10].

May Prevent Cardiovascular Disease

Large studies have found that vegetarians have a 1/3rd lower risk of heart disease compared to non-vegetarians [11].

It seems this benefit comes mainly from the reduction in saturated fat – prevalent in meat products – as cutting down on this nutrient reduces the risk of cardiovascular disease by ~20% [12].

Not only this, but many studies conclude that switching sources of saturated fat with either unsaturated fats, or whole grains, significantly reduces cardiovascular disease risk [13].

Saturated fat has the ability to raise blood cholesterol – directly linked to blocking the arteries – by increasing the amount of LDL cholesterol in the blood, increasing the rate of LDL cholesterol oxidation (causing inflammation), and reducing the number of LDL cholesterol receptors that would help to remove this cholesterol from the blood [14].

Dietary cholesterol from high intakes of meat may worsen this effect, as this substance facilitates the fatty deposit build-up on blood vessel walls by the increasing the uptake of LDL cholesterol particles into the arteries [15].

May Reduce Cancer Risk

Research suggests that vegetarian diets are associated with a lower overall incidence of all cancers, especially colorectal cancers [16].

There are several potential substances within meat that relate it to the progression of cancer, including heterocyclic amines, polycyclic aromatic hydrocarbons, N-nitroso compounds, and heme iron [17].

Although it is not conclusive, the main way meat may cause cancer is by producing mutagens which can potentially cause damage at a DNA-level. Theoretically, and what has been shown in animal models, is that this mechanism can induce the production of cancer cells and increase the size of tumors.

Meat consumption also considerably increases the production of reactive oxygen species within the body, which facilitates the survival of cancer cells and promotes the signaling for tumor growth [18].

Interestingly, in laboratory-based studies, the blood of plant-based eaters is 8 times less hospitable to cancer cells than those on a standard diet [19].

Potential Issues

Without a doubt, a well-planned flexitarian or other plant-based diet can be very healthy.

However, without adequate knowledge of important dietary considerations for this type of diet, the risk of nutrient deficiencies could increase. It really depends on the adequacy of food choices an individual chooses to make – however this argument could be made for any diet, not just plant-based.

Possible nutrient deficiencies to be aware of on the flexitarian diet include [20]:

Vitamin B12 deficiency in particular is notably prevalent in vegetarian populations, with >50% of vegetarians being deficient in this micronutrient [8]. This is due to this vitamin only being present in animal products. Therefore, depending on the amount of animal products a flexitarian chooses to include in their diet, a vitamin B12 supplement may be essential.

Flexitarians may also have lower stores of zinc and iron, as these minerals are best absorbed from animal foods. While it’s possible to get enough of these nutrients from plant foods alone, flexitarians need to plan their diets accordingly to accomplish this. Nuts, seeds, whole grains and legumes are great sources of iron and zinc and should all be staples in a flexitarian diet. Adding a source of vitamin C may also benefit iron absorption from plant-based foods.

If flexitarians choose to limit dairy and fish intake, they need to ensure calcium and omega-3 intake are being replaced by a suitable plant-based source.

The best plant-based calcium sources are kale, collard, tofu, and sesame seeds.

Omega-3 fatty acids on a flexitarian diet can be sourced from walnuts, almonds, chia seeds and flaxseeds.

Conclusion

The flexitarian diet describes a lifestyle where an individual actively looks to reduce their meat consumption, either for health, ethical, or environmental reasons.

The health benefits from such a diet are unknown, but it is logical to assume that the benefits will be similar to the vegetarian diet, albeit to a lesser extent.

The diet may help with weight loss, lower inflammation, and reduce the risk of cardiovascular disease and cancer.

Those following the diet should be aware they may be at an increased risk for deficiencies in vitamin B12, zinc, iron, calcium, and omega-3 fatty acids. Alternative plant-based foods or supplements should be consumed that contain these nutrients to avoid potential health issues.

Shaun Ward MSc BSc SENr Anutr
Shaun Ward MSc BSc SENr Anutr
Staff Writer & Fact Checker at DietProbe
Shaun is a registered nutritionist, and sport and exercise nutritionist, with experience in coaching professional endurance and strength athletes.
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Fact Checked


This article has been reviewed and fact-checked by a certified nutritionist, and only uses information from credible academic sources.