Adopting a vegan diet can be an overwhelming dietary balancing act. Not only do you need to deal with excluding a large proportion of common foods from your diet, but you also need to ensure that your new diet is nutritionally sufficient. Improperly replacing the nutrition in animal products can lead to feelings of tiredness for a variety of reasons. Although new vegans might suffer from this because of insufficient caloric and protein intake, deficiencies in iron and vitamin B-12 are more likely explanations for most vegans.
Your body's caloric needs are determined by a variety of factors, including genetics, your age, sex, body size, body composition and activity level. Eating too few calories can make you feel tired, as you might not be providing your body with the food energy that it needs. To help ensure that your vegan diet provides you with enough calories, you should try to eat more energy-dense foods. High energy-density foods contain at least 4 calories per gram and include most nuts, nut butters, seeds and seed butters. Cooking with vegetable oil is another easy way to boost your caloric intake, as vegetable oils contain nearly 10 calories per gram. Just be careful not to go over your recommended calorie intake to avoid weight gain.
Protein and Amino Acids
Like calories, insufficient protein should not be an issue for people following a balanced vegan diet. However, many vegan foods are poor sources of protein and particularly low in lysine, one of the essential amino acids. As fatigue is one of the symptoms of insufficient protein intake, it is possible that your tiredness arises from regularly eating too little protein. Avoiding this is relatively easy, as soy products, seitan, quinoa and most legumes are high in protein and good sources of the essential amino acids.
Iron is essential for transporting oxygen to all the cells in your body. Not consuming enough iron depletes your cells of oxygen, leading to iron deficiency anemia and intense feelings of fatigue. Unfortunately for vegans, the body has difficulties absorbing plant sources of iron. According to the National Institutes of Health's Office of Dietary Supplements, you can overcome this issue by eating nearly twice the recommended daily intake of iron. Vitamin C also increases your body's ability to absorb plant sources of iron. As such, you can make the most of high-iron vegan foods like soy products, lentils, beans, spinach, raisins and fortified breakfast cereals by pairing them with vitamin C-rich fruits and vegetables.
Like iron, vitamin B-12 is important for oxygen transport because it is essential for the formation of red blood cells. It also plays important roles in DNA synthesis and neurological health, both of which affect how tired or energetic you feel. A deficiency in vitamin B-12 is the most likely reason why you feel tired on a vegan diet, as no vegan foods naturally contain this important vitamin. Soy products, dairy alternatives and breakfast cereals that are fortified with vitamin B-12 are among the only ways to boost your B-12 intake. Another is nutritional yeast, a cheesy-tasting product that is rich in vitamin B-12 and available at most natural foods stores.
- The Dietitian's Guide to Vegetarian Diets: Issues and Applications, Third Edition; Reed Mangels, Ph.D., Virginia Messina, R.D., and Mark Messina, Ph.D.
- Canada's Food Guide: Estimated Energy Requirements
- British Nutrition Foundation: What Is Energy Density?
- Vegan Health: Protein
- Office of Dietary Supplements: Iron
- Office of Dietary Supplements: Vitamin B12
- U.S. Department of Agriculture: National Nutrient Database for Standard Reference, Release 25
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