Nutrition Problems in Vegetarians

Vegetarians may have problems in gaining weigh, since plants, in general, contain less calories than animal food.

Common Causes of Low Weight in Vegetarians

The low body weight in a vegetarian may be due to:

  • Low calorie intake, especially due to low fat intake
  • Avoiding eating due to non-attractive food
  • Irregular eating habits
  • Bloating due to large amount of soluble fiber resulting in avoiding food
  • Worm infestation
  • Small intestinal disorders, like celiac disease and fructose malabsorption

Why a Vegetarian May Refuse Food?

A. Food Related Causes

A vegetarian may refuse food for the following reasons:

  • Always having same type of food
  • Processed plant foods may not be tasty
  • Excess alcohol intake can cause low appetite
  • Antibiotics and chemotherapy, many medications like anti diabetic (metformin), narcotics

B. Health Disorders With Low Appetite

The causes of low appetite include:

  • Anemia due to iron deficiency or deficiency of vitamin B12, since vitamin B12 is found only in animal foods
  • Worm infestation that compromise intestinal absorption of nutrients
  • Psychological and psychiatric diseases like anorexia nervosa, depression
  • Infectious diseases, like HIV/AIDS, pneumonia, influenza, hepatitis, kidney infection
  • Serious illnesses, like cancer, liver diseases, kidney diseases, hypothyroidism, pancreatitis

C. Life Style and Psychological Reasons of Low Appetite

  • Busy working schedule
  • Depression, anxiety

D: Other causes of low appetite:

  • Smoking

How to Prepare for Appointment With a Doctor?

A vegetarian can expect the following questions from his doctor:

  • What is your current diet? (to evaluate calorie intake and iron and vitamin B12 intake)
  • What are your eating habits, how many meals per day do you have?
  • How is your appetite?
  • Have you ever had intestinal worms?
  • Do you have any chronic disease?

Recommended Tests Before Starting a Diet

Before starting a diet to gain weight, the following tests may be considered:

  • If you feel weak: blood level of iron, vitamin B12 and other vitamins, glucose
  • If you are bloated and have loose stools:
    • Stool test for ‘ova and parasites’
    • Breath test for fructose malabsorption
    • Breath test for small intestinal bacterial overgrowth (SIBO)
    • Breath test for lactose intolerance
    • Blood test for celiac disease
  • If you burp excessively and have burning feeling in the throat:
    • Breath test for Helicobacter pylori infection of the stomach

Vegetarian Foods That can Help Gain Weight

Plant foods rich in proteins:

  • Nuts: peanuts, hazelnuts, walnuts, almonds, pistachios, pecans, Brazil nuts
  • Seeds: sunflower, pumpkin
  • Legumes: soya bean, beans, peas, pulses, lentils, Bengal grams
  • Drumsticks
  • Cereals

The rich sources of fats of plant origin include:

  • Nuts: coconut and all other nuts
  • Seeds: all seeds
  • Avocado
  • Olives
  • Oil
  • Margarine

The rich sources of carbohydrates of plant origin include:

  • Cereals: rice, wheat, corn, millet, oats, barley, and so on
  • Pasta (macaroni, spageti)
  • Potato
  • Root vegetables, like beetroot
  • Dried fruits: raisins, dates, prunes, figs, apricots

Vegetarian Foods Rich in Iron

  • Enriched breakfast cereals
  • Enriched pasta
  • Beans and lentils
  • Baked potatoes with skin
  • Leafy greens of the cabbage family: broccoli, kale, turnip greens, collards
  • Dried fruits, like figs, raisins
  • Sesame seeds
  • Walnuts

Vegetarian Foods Rich in Vitamin B12

No plant foods contain vitamin B12, but several vitamin B12 enriched foods exist on the market. Vitamin B12 supplements are also available.

Foods to Avoid During Gaining Weight Attempt

The following foods may be problematic, when you want to gain weight:

  • Foods that may produce a lot of gas:
    • Foods high in soluble fiber: beans, oats
    • Carbonated drinks, like beer
    • Foods, high in fructose or sorbitol (especially in those with fructose malabsorption): honey, apples, pears, peaches, plums and prunes, dried fruits in general, ‘diet soda’ and other ‘low calorie’ foods sweetened by sorbitol

Meals Proposals for Skinny Vegetarians

While trying to gain weight, the breakfast and lunch/dinner should be like this:


  • 200-300 gm of bread (2-3 slices or 2-3 chapatis for Indians)
  • About 100 gm of sprouting beans/grams
  • A glass of milk (250-300 ml) with 10-15 gm of sugar or a cup of tea/coffee
  • High calorie fruits like bananas 2-3 big size


  • 200-300 gm of rice or wheat (roti)
  • 50 gm of leafy vegetables
  • 75-100 gm of other vegetables
  • Pulses about 50 gm
  • Cooking oil like sunflower oil, ground nut oil, safflower oil, and so on
  • Milk or curd 100 gm/ml


In between major meals few servings are advisable.


Some vegetable juices are high in calories and can be healthy. Fruit juices usually contain a lot of sugar and can often cause bloating.

Alcohol in general contains a lot of calories, but drinking excess alcohol is not a good method of gaining weight. A glass of red wine after a dinner can stimulate digestion, so it can be healthy.

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Article reviewed by Dr. Greg. Last updated on December 17, 2011