Low carb plant-based diet – what to eat?
By Dr Shireen Kassam, Director of Plant-Based Health Professionals UK
The consensus on diet quality has remained unchanged for decades. Healthy diets are those that emphasise the consumption of fruit, vegetables, whole grains, legumes, nuts and seeds, whilst minimising/avoiding red and processed meat and foods high in saturated fat, salt and sugar. This way of eating can be adapted to all cultural and traditional diet patterns including Mediterranean, Asian, African, flexitarian, plant-based and more.
For some people, lowering the proportion of carbohydrates in the diet can help with achieving certain health goals, such as weight loss or better lipid and glucose control.
Diets lower in carbohydrates, or low-carb diets, have caught on in the UK, especially for the management of type 2 diabetes. However, the diet is not without its concerns, especially in the long-term, if not adequately planned.
Definition of a low-carb diet
There is no standard definition of a low-carb diet, but in general it is a diet that has a carbohydrate intake of <130 g/day or <26% of total energy.
The rest of the diet will come from different proportions and sources of fat and protein. The types of high fat and high protein foods consumed will determine the impacts they have on health.
Misguided fear of carbohydrates
Not all carbohydrate-rich foods are created equal. The carb-rich foods associated with poor health are those low in fibre and high in refined sugar and refined grains. This includes sugar-sweetened beverages, white bread, cakes and pastries. In contrast, whole or minimally processed plant foods such as fruit, vegetables, whole grains and beans, which are also high in various types of carbohydrates, are some of the healthiest foods you can eat. This is because they come packaged with fibre and an array of vitamins, minerals and other phytonutrients that are associated with better physical and mental health and a reduced risk of chronic conditions.
When diets composed of different macronutrient ratios have been compared, such as low-fat versus low-carb diets, the data consistently show that diet quality matters more. Diets lower in fat or lower in carbohydrates can both support better cardiovascular health, weight loss and prevention and treatment of type 2 diabetes.
Health impacts of a low-carb, animal-based diet
In the short term, low-carb diets have been shown to result in weight loss and improve blood sugar regulation, in part, because there is reduced consumption of ultra-processed foods high in free sugars and refined grains. However, when compared to high quality low-fat diets with a balanced range of carbohydrates, there does not appear to be any special advantage for weight loss in people with or without type 2 diabetes.
Concerns arise when carbohydrates are replaced by animal sources of protein and fat. This can result in nutritional deficiencies due to the lower intake of plant-based foods, including folate, vitamins C and K, magnesium and fibre deficiency.
In addition, numerous studies have shown that when low-carb diets result in higher intakes of saturated fat, found predominantly in animal-sourced foods, this leads to elevated blood LDL-cholesterol levels. Elevated LDL-cholesterol is a major risk factor for atherosclerotic cardiovascular disease, including heart attacks and strokes. This is likely to be why some studies have reported greater evidence of coronary artery atherosclerosis in people following a low-carb diet.
Long-term concerns from observational studies include higher rates of all-cause, cardiovascular and cancer-related mortality with animal-based low-carb diets – that means, a higher chance of premature death.
Animal-based low-carb diet versus plant-based diet
An important metabolic ward study tested a low-fat plant-based diet head-to-head with a low-carb animal-based diet. The 20 participants could eat as much as they wanted during the two week period, with each participant trialling both diets.
On the plant-based diet, participants consumed significantly less calories. Both diets led to improvements in fasting glucose and insulin levels, but the plant-based diet resulted in greater weight and body fat loss and improvements in cholesterol levels. The low-carb group lost mainly water weight and muscle mass, developed a degree of insulin resistance, had higher postprandial triglyceride levels and a rise in LDL-cholesterol levels. The low-carb diet did improve fasting triglyceride levels, which worsened on the plant-based diet.
A healthy low-carb diet
For some people, there may be advantages to adopting a low-carb plant-based diet. Higher intakes of plant sources of fat, particularly polyunsaturated fats such as omega-3 and omega-6 fatty acids can result in lower triglyceride and LDL-cholesterol levels. Additionally, higher protein intakes may help with satiety, which may support weight management. Higher protein intakes may be especially useful for individuals using GLP-1 medications for weight loss, and this can help to prevent muscle loss when combined with regular strength training.
Low-carb plant-based diets have been coined and studied under the name Eco-Atkins, a diet that contains increased protein and fat from gluten and soya products, nuts and vegetable oil. In both a 4 week and a 6-month randomised controlled trial, the Eco-Atkins diet resulted in greater lowering of triglycerides and LDL-cholesterol when compared to a high-carb lacto-ovo vegetarian diet. However, it’s worth noting that these studies, albeit randomised, are small, with the longer-term one having a high drop-out rate.
As mentioned previously, lowering carbohydrates, even in the context of a plant-based diet does not appear to have additional benefits for weight loss if the diet is focussed on minimally processed plant-based foods.
Long-term health outcomes of a plant-based diet
Observational studies have consistently shown that populations consuming a mostly or exclusively plant-based diet have better health outcomes, including lower rates of coronary heart disease, overweight and obesity, type 2 diabetes, certain cancers and a reduced risk of early death. This is regardless of the macronutrient ratio of the diet.
A good example comes from the Blue Zones, regions around the world where people live the longest and healthiest lives. People in Ikaria, Greece tend to eat a higher fat diet, specifically high in extra virgin olive oil. In contrast, people in Okinawa, Japan, eat a very high carbohydrate diet with the purple sweet potato being a major source of energy. What the diet of the Blue Zones have in common is that they are predominantly or entirely based around fruit, vegetables, whole grains, beans, nuts and seeds.
Summary
- Diet quality remains more important than macronutrient ratios.
- Low-carb diets are currently recognised by UK guidelines as one evidence-based option for the management of type 2 diabetes and for supporting weight management in people living with overweight or obesity.
- Some people may find that a low-carb diet helps them to achieve their health goals.
- Diets high in animal-sourced fats and protein are associated with poorer health outcomes in the longer-term.
- If lowering carbs in the diet, they should be replaced by plant sources of protein and fat.
- It is best to first discuss with a registered dietitian or healthcare professional before changing your diet.
How to adopt a healthy low-carb diet
Healthy low-carb foods
- Vegetables: artichokes, asparagus, aubergine, broccoli, brussels sprouts, cabbage, cauliflower, celery, courgettes, cucumber, garlic, green beans, kale, leeks, lettuce, mushrooms, onions, peppers, pumpkin, radishes, soya beans, spinach, tomatoes
- Fruits: avocado, blackberries, olives, raspberries, strawberries
- Protein/fat: almonds, almond milk, brazil nuts, chia seeds, flax seeds, hazelnuts, hemp seeds, macadamia nuts, pecans, pine nuts, pumpkin seeds, sesame seeds, soya milk, sunflower seeds, tempeh, tofu, walnuts, yoghurt, nut butters
- Pasta: made from edamame, lentils, chickpeas, beans or pea protein
- Flours: made from naturally low carb food sources such as lupin or almond flour
- Dips: hummus, bean salsa, guacamole
- Condiments/flavouring: chilli powder, cinnamon, cocoa, herbs, mustard, pesto (vegan version), spices, tomato puree, vinegar, vanilla extract
Coconut is low carbohydrate but should be consumed in moderation as it contains saturated fat. A small amount of oil occasionally for a particular favourite recipe probably does no harm for most people.
Plant-based low-carb breakfast ideas
- Smoothies – start with a base of fortified soya milk, soya yoghurt, or silken tofu and water, then add your preferred fruits and veggies such as berries, spinach, kale, cucumber or avocado, and add flaxseeds, chia seeds, or hempseeds for unsaturated fats. A squeeze of lemon or vanilla extract can also add extra flavour!
- Chia seed pudding – soak chia seeds overnight in fortified soya milk and top with berries, nuts, seeds, or nut butter. Optionally add vanilla extract and/or cocoa powder to taste. A great option for meal prepping in advance.
- Tofu scramble – lightly fry some crumbled tofu with veggies such as spinach, mushrooms, tomatoes, and avocado.
- Soya yoghurt bowl – top soya yoghurt with nuts, seeds, and fruit
- If you’ve got a bit longer to make breakfast, try a tofu shakshuka recipe or chickpea flour omelet
Plant-based low-carb main meal ideas
- Salads – start with a base of dark leafy greens, top with a quality protein source such as marinated tempeh or tofu, add your preferred veggies, nuts, and seeds, and top with some hummus, guacamole, or dressing
- Soups – start with a base of non-starchy vegetables (e.g. cauliflower, courgette, spinach or broccoli) blended with vegetable stock, then blend in protein such as silken tofu, and flavour with herbs, spices, and healthy fats like olive oil or seeds.
- Bean-free chilli made with soya mince, mushrooms, peppers, and a side of avocado
- Baked tofu with roasted low-carb vegetables such as asparagus, broccoli and cauliflower and tahini dressing
- Tofu satay made with firm tofu and a sauce of peanut butter, garlic, lime juice, and water, served with a stir-fry of non-starchy vegetables.
- Thai-style vegetable and tofu curry with a small portion of brown rice
These are just some ideas to get you started with finding plenty of free recipes online!
Low-carb snacks
- Nuts and seeds
- Protein balls
- Olives
- Edamame beans
- Nut butter with celery sticks
- Hummus, guacamole or salsa with low carb veggie sticks
- Unsweetened soya yoghurt topped with berries
- Berries with chocolate dipping sauce (made from a combination of peanut butter, cocoa powder, vanilla extract and a splash of water)
- 70% plus dark chocolate
Low-carb plant-based meal plan example*
| Breakfast | Chia seed pudding:
2 tbsp chia seeds, 1 cup unsweetened, fortified plant-based milk, sprinkle of cinnamon, 2 tbsp nut butter and handful fresh berries |
| Snack | 1 pot (8 tbsp) fortified soya yogurt and 2 satsumas or 1 apple |
| Lunch | Green salad:
Two handfuls of dark leafy greens (kale, spinach), a cup of roasted calcium-set tofu cubes, 1 carrot, ¼ cucumber, 2 spring onions, 7 olives, 2 tbsp plant-based mustard vinaigrette dressing, 3 tbsp hummus, 3 tbsp of toasted almond flakes and a slice of rye bread. |
| Snack | 2 slices honeydew melon + 1 handful of nut mix |
| Dinner | Butternut squash and borlotti bean stew (per serving):
¼ butternut squash, ½ red onion, ¼ green pepper, ½ tin of can tomatoes, 1 tbsp dried red lentils, ½ tin of barloti beans drained can beans clove of garlic, pepper to taste, chopped parsley and 1 tbsp olive oil. |
| Dessert | 5 squares of 70% dark chocolate and 1 cup of berries |
| Total composition | |
|---|---|
| Carbohydrates: | 125g |
| Proteins: | 71g |
| Fibre | 54g |
*Portions based on a standard 2000Kcal daily intake designed by Carbs & Cal app. This low-carb plant-based meal plan is intended for educational purposes only.