Weight Gain Diet Tips for Vegetarians

Nutrition Problems in Vegetarians

Some vegetarians experience a problem with gaining weight and this is believed to be due to a vegetarian diet. It could be associated with a lower protein intake as well as a lower calorie intake, however, there may be other factors at play as well which do not involve a vegetarian diet.  Although obesity can also afflict vegetarians and vegans, studies have indicated that it is lower among these groups ¹.

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 reduced appetite.
  • Irregular eating habits.
  • Bloating due to large amount of soluble fiber resulting in avoiding food
  • Worm infestation with regularly consuming raw foods.
  • Small intestinal disorders, like celiac disease and fructose malabsorption.

Not all of these causes are unique to vegetarians or vegans.

Why a Vegetarian May Refuse Food?

A. Food Related Causes

A vegetarian or vegan who is still adapting to a primarily plant-based diet may eats less due to:

  • Always having same type of food (among individuals who are not culinary creative).
  • Vegatables, fruits and processed plant foods may not seem as appetising (individual preference).
  • Nutritional deficiencies as a result of not maintaining a balanced diet.

In addition, medical conditions and medication may further reduce appetite, which is not specific to vegetarians or vegans.

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. Lifestyle and Psychological Reasons of Low Appetite

  • Busy schedule.
  • Lack of access to convenience vegetarian/vegan foods.
  • Inability or lack of interest in preparing meals.
  • Depression and other mental health conditions.
  • Substance abuse.

How to Prepare for Appointment With a Dietitian?

A vegetarian or vegan who is experiencing difficulty gaining weight should consult with a registered dietitian. The following information may be helpful:

  • 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?
  • What are your food preferences or dislikes based on individual taste, cultural, affordability and accessibility factors?

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. Furthermore there is vitamin B12 within milk and dairy products. Vitamin B12 supplements are also available. If necessary and approved by a medical professional, regular vitamin B12 injections may be administered.

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

The first dietary consideration is to ensure sufficient calorie intake in a day. For adult males, this is approximately 2,500 calories a day with a moderately active lifestyle and for adult females with the same lifestyle it is approximately 2,000 calories daily. Furthermore there should be sufficient protein intake and suitable fat intake on a daily basis.


  • 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


Snacks that are approximately 100 to 200 calories can be consumed between meals. However, these snacks should not cause the daily calorie intake to be exceeded.


Water is probably one of the best beverage choices from a health perspective, provided that it is clean. However, water has no calories in its pure state. Other beverages may also be included into the diet. Some vegetable juices are high in calories and can be healthy. Fruit juices usually contain a lot of sugar and can often cause bloating and even lead to excess weight gain. Protein powders may also be added to certain beverages to increase protein intake, even if a person does not consume milk or any dairy products.

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