3 reasons why people abandon a plant-based diet (and what to do about it..)


You may have noticed more plant-based options appearing on the menu, celebrities and athletes announcing that they have decided to go meat free, you have read books/articles on how a whole foods plant-based diet can reverse most chronic diseases and even enhance athletic performance. Make no mistake, a plant-based diet is not another diet fad but a nutritional perspective here to stay.

With all the buzz about going meat free, some decide to test drive ‘going vegan/plant-based‘ and fall short. They either end up reintroducing some animal products after a while or…giving up totally and going back to where they were before. In my experience, here are the top 3 reasons I believe..why some abandon a plant-based diet.


Reason 1: Lethargy

“My energy levels are so low, I feel like sleeping all day.“

Source: Mangomannutrition.com

Plant-based foods are less calorically dense than animal based foods. Take for example, a 100g of chicken breast yields 165 calories, compared to a 100g serve of tofu which yields 76 calories and with spinach, that would be a 23 cup serve. No I am not suggesting for anyone to substitute chicken breast for spinach but just to be aware that deciding to go meat free, you might unintentionally put yourself in a calorie deficit. So salads alone won’t quite cut it.

The concept I would like to introduce you to is calorie density. Calorie density quite simply put, is the amount of calories per pound of food. Foods high in calorie density contain a lot more calories in a small weight, while foods low in calorie density contain much less calories in a larger weight. Meat, fish, dairy, processed and refined foods have higher calorie density as compared to legumes, fruits and vegetables. Another way of describing calorie density as written by Diabetes coach Cyrus Khambatta pHd, is “the number of calories per bite in a given meal.

The other reason why you might feel lethargic is because all your calories come from ‘vegan junk foods’. From processed/faux ‘meats’, to dairy free chocolates & ice cream, potato chips and fried foods. These foods yield high calorie density while providing zero to no nutrition.

What to do…

  1. Start getting the bulk of your calories from higher calorie density whole plant-based foods. Things like whole grains (eg: pasta, rice, bread, cereals), root vegetables (eg: potatoes, yam, taro), legumes (eg: tofu, tempeh, bean varieties), fruits (eg: mangos, dates, bananas) while filling in the gaps with nuts and seeds (eg: pumpkin seeds, hemp seeds, walnuts, almonds). These plant-based foods will form the base of your calories while you have an unlimited amount of fibrous vegetables and leafy greens.

  2. If you are into calculating your daily intake, it’s worth tracking your nutrition. The first thing you can do is to establish your basal metabolic rate. Your BMR is the total number of calories that your body needs to perform basic, life-sustaining functions (respiration, circulation, digestion) daily. Once you have your BMR, you can take a daily food log and input into sites/apps like MyFitnessPal or Cronometer. Record your total daily calorie intake for 3 days then divide it by 3 to get your average daily caloric intake. Cross reference it with your BMR to see where you are falling short, whether you are in a calorie deficit.


Reason 2: Loss of muscle or strength


“I’m losing size or strength.” or “I am not getting enough protein.”

Often this could be attributed to being in a calorie deficit. So like above, it’s worth tracking your daily intake to see whether you are consuming sufficient calories from whole plant-based foods.

In terms of protein RDI, a sedentary male up to the age of 70yrs requires 0.84g/kg of bodyweight of protein per day while for a female, the RDI would be 0.75g/kg of bodyweight (this works out to approximately 10% of total calories consumed). This can easily be met by consuming sufficient calories on a whole foods plant-based diet.

So, what if you are extremely active and perform strength based activities (eg: bodybuilding, powerlifting, crossfit)? Well, your protein requirements will be higher. After interviewing several plant-based sports nutritionist, registered dieticians and athletes, I’ve learned that endurance athletes may require anywhere from 1.2-1.4g/kg of bodyweight, while strength athletes may require anywhere from 1.6-1.8g/kg of bodyweight.

While a low carb/ketogenic diet can help individuals achieve body composition goals, it is important to note that a weight loss/low body fat percentage does not necessarily equate to health and longevity. Excess protein consumption (particularly from animal based sources) has been shown to be detrimental to long term health, contribute to chronic illness (1) (2) (3) and also accelerate ageing through several pathways (IGF1, TOR-S6K and PKA) (4). More on this topic here.

Beyond this, the apparent ‘loss of size’ could also be subjective. Majority of animal based proteins come from the industrialised farming system. Factory farmed animals are often grain fed (not their natural diet - this grain is often GMO and rich in pro-inflammatory Omega 6s) and injected with hormones to fatten them up for quicker yields. As a result, the appearance of ‘increased muscle mass’ could be due to the hormones (synthetic and naturally occurring) present, and the inflammation of muscle cells.

What to do…

The myth of plants being ‘incomplete protein’ sources has now been debunked. Your body has the ability to recycle amino acids throughout the day. If your goal is health, as long as you are consuming sufficient calories from a varied whole foods plant-based diet, you will get all 9 essential amino acids for daily function.

However, if you are an extremely active individual, put a daily emphasis on legumes, raw nuts and seeds. Depending on your goals, you might consider supplementing with a plant-based protein powder.

The eternal question….So where do you get your protein?

To give you an idea of how I hit my ‘protein goals’, I will share with you my daily intake. Weighing 80kg, I train 6 times a week (crossfit, calisthenics, running/swimming). My BMR is about 3150 calories per day.


Oats with pumpkin seeds, berries and plant-based protein powder with soy milk


Rice and beans for lunch with lots of vegetables


Mangos and oranges for snacks


Whole grain tomato pasta with tofu and vegetables

Total calories consumed: 3109 calories

Macro split of calories:

C: 477.8g F: 50.3g P: 145.3g

Using the RDI above of 1.8g/kg x bodyweight - 1.8 x 80kg =

144g of protein per day


Reason 3: Overall decline in mental/physical health

“I’ve added some meat into my diet and i feel better.” or “I’m feeling depressed.”


There could be several reasons why this might be the case. Anywhere from consuming insufficient calories, vitamin/mineral deficiencies or allergies/intolerances, lack of nutrient diversity or lack of social support. The other factor could be the pressure you put on yourself to do it ‘perfectly’. Entering the world of plant-based eating can be daunting on it’s own and then, you are exposed to plant-based perspectives like..

Raw veganism - Focussing on fruits, vegetables, nuts, seeds, sprouted grains and legumes. Foods are minimally processed eaten completely raw or heated at temperatures below 104–118°F (40–48°C).

801010 - Where 80% of your calories from carbohydrates (primarily raw fruit) 10% each from raw, plant-based protein and fat.

Starch based - Focussing on getting the bulk of your calories from whole grains, legumes and starchy vegetables (eg: rice, potatoes corn) while keeping fats low.

SOS free - A whole foods plant-based diet that is free from added Salt, Oil and Sugar.

…just to name a few. Beyond that some even add increased complexity by being overly obsessed with aspects like extended juice/water fasts, drinking only alkaline water and eating only organic produce.

The decision to go meat free can be a huge leap for some and to now be exposed to all these labels and rules…it’s hard to know where to start let alone know what to do.

What to do…

  1. Vitamin/mineral deficiencies/allegies/intolerances -

    • Ensure that you get some blood work done by a health care professional to check if there are any other pre-existing vitamin/mineral deficiencies that need to be addressed. The other thing to look out for is potential allergies/intolerances that could impair or impact digestion and nutrient absorption/assimilation.

    • Common deficiencies in a plant-based diet are vitamin B12 and D. Make sure you supplement with B12, D (if you do not get sufficient sunlight) and incorporate Omega 3 rich foods (ground chiaseeds/flaxseeds, walnuts, leafy greens, hemp seeds) and plant-based sources of zinc (pumpkin seeds, legumes). More in this article.

    • Some individuals choose to include an Omega 3 EPA-DHA (Derived from Algae, AHI Flower) supplement while others consume a daily multivitamin to cover all bases.

  2. Lack of nutrient diversity -

    • Focus on eating the rainbow. Colours represent nutrient diversity of plant-foods (eg: red, green, yellow, purple, orange).

    • Eat locally and seasonally where possible. By doing so produce will be cheaper, fresher and more nutrient dense. This will also help prevent allergies since your diet will be varied.

  3. Lack of social support -

    • Connect with your local meet up groups or join online forums to get the support and inspiration you need.

  4. Being ‘perfect’ -

    • As Dr Pamela Popper once said “If there is a one size fits all diet out there, it would be a whole food plant-based diet.” or at least, variations of it. Sometimes raw veganism, 801010, starch based etc.. works until it doesn’t. This could be due to the factors like climate, geography, fitness goals, change in palate, hormonal balance etc..the main thing is to try different approaches without giving up altogether. Keep reading, researching, experimenting and if need be, engage a plant-based health/nutrition coach to help you on your journey. Progress is always better than ‘perfection’.

Rather than look at going going plant-based as eliminating foods that you normally eat, treat this as an adventure, a way to add more colour and nutrients into your day. I wish you the best in your plant-based journey!

Yours in health and happiness,

Luke Tan

If you are fitness professional or interested in learning about optimising a plant-based diet for better health and fitness, join me at the upcoming Fundamentals of Plant-based Nutrition for Fitness course conducted with Fit Singapore. Click the image below for more information.