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5 Mistakes To Avoid On A Vegetarian Diet

It is thought that a well-balanced vegetarian diet can provide you with numerous health benefits and vegetarian diets have been associated with weight loss, better control of blood sugar, a decreased risk of heart disease and lower risk for certain types of cancers (1, 2, 3, 4).

Top 5 mistakes which should be avoided on vegetarian diets

1. Assuming That Vegetarian Products Are Healthier

Just because a product comes with the label of vegetarian, doesn’t necessarily mean that it is the healthier alternative to the regular product. For example one cup of cow’s milk contains eight grams of protein, whereas unsweetened almonds milk can contain only one gram (5, 6). Sweetened almond milk contains high sugar content with sixteen grams of sugar in one cup (7). Although the presence of vegetarian alternative products may make the transition to a vegetarian diet easier, they should be consumed in moderate amounts as they are often highly processed and lack nutrients.

2. Not Consuming Enough Vitamin B12

Vitamin B12 plays many important roles in the body, including in the creation of red blood cells and DNA (8). However B12 is usually derived from animal products and vegetarians are at an increased risk of developing a vitamin B12 deficiency (9). This kind of deficiency can cause symptoms such as fatigue, memory loss and physical numbness; it can also lead to megaloblastic anaemia (10).

Other than animal products, fortified foods and edible algae can contain vitamin B12 (11). Vegetarians should ensure that they monitor their vitamin B12 intake carefully otherwise consider taking supplements if their requirements are not met through diet.

3. Eating Too Few Calories

As many foods and food groups are unsuitable for vegetarians, it can be challenging to meet calorie needs. As a result vegetarians often end up consuming fewer calories than those who follow a meat-inclusive diet. Calories are the main source of energy for your body and your body must consume a certain amount in order to function correctly. By restricting calories too much, you can suffer from several negative and detrimental side effects such as nutritional deficiencies, exhaustion and a slower metabolism (12, 13, 14).

4. Forgetting About Iron Intake

Meat is an excellent source of many important vitamins and minerals which includes iron. For example, an eighty five gram serving of ground beef can supply your body with fourteen percent of all the iron that you will need for the whole day (16). Vegetarians have an increased risk of developing iron-deficiency anaemia, which presents with symptoms such as fatigue, shortness of breath and dizziness (17). By planning your vegetarian diet well and filling it with iron-rich plant foods such as lentils, beans, fortified cereals and leafy greens you can meet your daily needs. Additionally, by pairing foods which are rich in iron with vitamin C can enhance absorption of iron. (18).

5. Not Consuming Enough Protein

You’ve most likely heard this one before, however protein is undeniably an essential part of your diet. Your body requires protein to help you build tissue, create enzymes and hormones. Studies have shown that by eating protein, you can promote feelings of fullness, increase your muscle mass and also reduce food cravings (19, 20). The current UK recommendations that adults should be eating 0.75 grams of protein per day for every kilogram of their body weight (21). This is a lot easier to do if you are eating meat and when following a vegetarian diet you should make a conscious effort to consume high protein foods which help you meet your protein requirements. Foods such as beans, lentils and nuts can all help to increase your daily intake of protein, so try and incorporate at least one of these foods into each meal to ensure you’re consuming enough.

For more information on potential mistakes you could be making by following a vegetarian diet, see our weight loss management course.


  1. Huang, R.Y., Huang, C.C., Hu, F.B. and Chavarro, J.E., 2016. Vegetarian diets and weight reduction: a meta-analysis of randomized controlled trials. Journal of general internal medicine, 31(1), pp.109-116.
  2. Barnard, N.D., Cohen, J., Jenkins, D.J., Turner-McGrievy, G., Gloede, L., Green, A. and Ferdowsian, H., 2009. A low-fat vegan diet and a conventional diabetes diet in the treatment of type 2 diabetes: a randomized, controlled, 74-wk clinical trial–. The American journal of clinical nutrition, 89(5), pp.1588S-1596S.
  3. Le, L.T. and Sabaté, J., 2014. Beyond meatless, the health effects of vegan diets: findings from the Adventist cohorts. Nutrients, 6(6), pp.2131-2147.
  4. Orlich, M.J., Singh, P.N., Sabaté, J., Fan, J., Sveen, L., Bennett, H., Knutsen, S.F., Beeson, W.L., Jaceldo-Siegl, K., Butler, T.L. and Herring, R.P., 2015. Vegetarian dietary patterns and the risk of colorectal cancers. JAMA internal medicine, 175(5), pp.767-776.
  8. Smith, E.L., 1965. Vitamin B12. Vitamin B12., (Ed. 3rd).
  9. Herrmann, W. and Geisel, J., 2002. Vegetarian lifestyle and monitoring of vitamin B-12 status. Clinica Chimica Acta, 326(1-2), pp.47-59.
  11. Watanabe, F., Yabuta, Y., Bito, T. and Teng, F., 2014. Vitamin B12-containing plant food sources for vegetarians. Nutrients, 6(5), pp.1861-1873.
  12. Alexander, N.B., Taffet, G.E., Horne, F.M., Eldadah, B.A., Ferrucci, L., Nayfield, S. and Studenski, S., 2010. Bedside‐to‐Bench Conference: Research Agenda for Idiopathic Fatigue and Aging. Journal of the American Geriatrics Society, 58(5), pp.967-975.
  13. Fothergill, E., Guo, J., Howard, L., Kerns, J.C., Knuth, N.D., Brychta, R., Chen, K.Y., Skarulis, M.C., Walter, M., Walter, P.J. and Hall, K.D., 2016. Persistent metabolic adaptation 6 years after “The Biggest Loser” competition. Obesity, 24(8), pp.1612-1619.
  14. Rosenbaum, M. and Leibel, R.L., 2010. Adaptive thermogenesis in humans. International Journal of Obesity, 34(S1), p.S47.
  17. Hallberg, L., Brune, M. and Rossander, L., 1989. The role of vitamin C in iron absorption. International journal for vitamin and nutrition research. Supplement= Internationale Zeitschrift fur Vitamin-und Ernahrungsforschung. Supplement, 30, pp.103-108.
  18. Blom, W.A., Lluch, A., Stafleu, A., Vinoy, S., Holst, J.J., Schaafsma, G. and Hendriks, H.F., 2006. Effect of a high-protein breakfast on the postprandial ghrelin response–. The American journal of clinical nutrition, 83(2), pp.211-220.
  19. Pasiakos, S.M., McLellan, T.M. and Lieberman, H.R., 2015. The effects of protein supplements on muscle mass, strength, and aerobic and anaerobic power in healthy adults: a systematic review. Sports medicine, 45(1), pp.111-131.
  20. Leidy, H.J., Tang, M., Armstrong, C.L., Martin, C.B. and Campbell, W.W., 2011. The effects of consuming frequent, higher protein meals on appetite and satiety during weight loss in overweight/obese men. Obesity, 19(4), pp.818-824.
  21. Wu, G., 2016. Dietary protein intake and human health. Food & function, 7(3), pp.1251-1265.