Obesity has reached epidemic proportions around the world.
In the US, over 70% of adults over 20 years old are overweight or obese (1). This is a huge public health issue, and a daily struggle for individuals living with obesity. The stats show how hard it is to maintain, or return to, a healthy weight.
Along with the health issues associated with obesity, like type 2 diabetes and cardiovascular disease, people may struggle with daily tasks, as well as feeling comfortable in their own skin.
Clearly, what we’re currently doing to try and fix the problem isn’t working.
The idea that only calories matter is not helping, and it leaves people feeling constantly restricted. If your diet consists of processed and animal foods, like the typical western diet does, and you decide to lose weight by eating 500 fewer calories a day, it probably won’t help much in the long-run. Given the amount of animal and processed foods your body still has to deal with, not to mention constantly feeling hungry, as you won’t increase your insulin sensitivity, get more satiating cues from your appetite hormones, or store less of that food as fat.
A whole-food plant-based lifestyle is the best way to combat obesity, it focuses on what you eat - not just how much you eat - and with the right approach, it can change your life,
Not just for now, but forever.
How does a plant-based diet help weight loss?
Less overall calorie consumption
Whilst calories aren’t the only thing that matters, it’s still an important aspect of losing weight. Eating fewer calories can result in a better balance between the number of calories coming in, and what’s being burnt. This means less energy is stored as fat, and some of the excess energy stored as fat will begin to disappear.
If you want to continue eating hearty-sized portions, but keep calories low, plant-based meals are your golden ticket. Plant foods are naturally less energy dense (lower in calories) than animal-derived or processed foods. So, when you center a meal around whole plant-foods, you can eat the same volume but with naturally lower calories (2) (3). Eat bigger portions with fewer calories? Sounds like an ideal scenario.
More water, more fiber
The reason plant foods are lower in calories is because they have a higher water and fiber content than animal-derived foods. Fiber really is the dietary key to weight loss - it adds bulk to food without adding calories. Fiber also improves the health of your gut microbiome, which further promotes weight loss (4). Animal-derived foods are completely devoid of natural fiber, and contain higher levels of saturated fat, making them more energy dense. You’re more likely to consume more calories daily, without even realizing, if your meal consists of low fiber animal-derived foods.
Feeling fuller for longer
But, surely if there’s fewer calories you’ll just feel hungry sooner after the meal? Wrong! Evidence shows us that plant-based meals leave you feeling more satiated and fuller for longer. Plant-based meals are better at regulating our appetite hormones. They increase the levels of our gut hormones, namely glucagon-like peptide-1 (GLP-1), amylin, and peptide YY (PYY), after a meal, meaning we get fewer ‘I’m hungry’ signals during the day (5).
Plant-foods give your metabolism a boost
Everyday, we burn around 60% of our total calories just by carrying out necessary functions, such as breathing, keeping our blood flowing, and digesting and utilizing our food. Around 10% of daily calories burned is from breaking down and utilizing our food - known as the thermic effect of food (6). Research shows us that eating plant-based meals can actually increase the number of calories burned after a meal, i.e. it increases the thermic effect of food (7) (8). This is because people who eat plant-based are more insulin sensitive, and the lower fat content of most plant-based meals allows the mitochondria in our cells to work more efficiently.
Basically, if you’re plant-based you can burn more calories… just by eating!
You’ll find yourself eating less saturated fat (and cholesterol)
Apart from a few exceptions (such as coconut oil, palm oil, and cashew nuts), plant-based foods are much lower in saturated fat than animal-derived foods - the main source of saturated fat in the American diet. This helps to improve insulin sensitivity, and increase the thermic effect of food, which helps with weight loss (9).
You are likely to consume more vitamins, minerals and antioxidants
As well as being low in saturated fat, plant-foods, such as fruits and vegetables, are abundant in nutrients. One worth a mention is polyphenols, a bioactive compound which can help to improve satiety after a meal, as well as insulin sensitivity, the thermic effect of food, and reduce body weight (9).
Where’s the evidence that this actually works?
Obesity is uncommon in individuals eating a plant-based diet.
A huge study of over 70,000 people found that vegans had the lowest BMI, and the fewest weight problems, compared to vegetarians, pescatarians, semi-vegetarians, and omnivores (10). In a randomized weight loss trial, women put on the plant-based diet lost more weight than the moderate low-fat diet, which included lean meat, both at 1 year and 2 years after the study began (11). The same was seen in overweight men, where weight loss on the vegan diet was significantly greater than the omnivorous, semi-vegetarian, and pesco-vegetarian diets (12).
Diet plans are hard to stick to, and it’s easy to fall back into old habits, how is this any different?
Many of the ‘quick fix’ weight loss programmes and diets offered today may help in the short-term, but they’re rarely sustainable ways to create long-term change.
That’s where a plant-based diet is different. You can start to see changes quickly, but with a focus on the long-term, it allows you to continue enjoying cooking, and eating, but with added health benefits. Because of the fiber content, you will continue to feel full and satisfied after your meals, and that won’t change over time. You won’t feel constantly restricted and like you want to break into old habits, as a plant-based diet can be very effective for weight loss without limiting calories (13). If you’re just starting out, you don’t have to be 100% plant-based; gradual, small changes can still help you to lose weight (14), and maintain it in the long-run (11).
Tips for losing weight on a plant-based diet
Dr Laurie Marbas, our Chief Medical Officer, shared her top tips for losing weight on a plant-based diet:
- Processed vegan foods - whilst these can be good transitional foods, they're generally no good for our health. Limiting these foods as much as possible will be a huge help on your plant-based weight-loss journey.
- Inclusion of oil - 1 tbsp of oil is 120 calories of pure fat. This gets absorbed into our cells and stored as fat, saved up for a rainy day. Dr Marbas recommends removing oil where you can if you’re trying to lose weight, to limit the build up of fat in our cells.
- Snacking - Food is so abundant these days that it’s easy to practice mindless eating - we’re eating almost all the time, whilst watching tv, driving, watching our kids play sports, and even whilst cooking. It’s often easier to reach for those ready-to-go processed foods too. Try to avoid snacking which will reduce your calorie intake, or swap for fruit and veg snacks.
- Drinking our calories - stuff like starbucks coffees can contain more calories than we realize, be mindful of these and what you’re adding in terms of sweeteners, creamers etc. Drink smoothies slowly and give yourself time to feel satiated.
- Too much calorie-dense plant-foods - whilst nuts, avocados, and nut butters are healthy and an important part of the diet, you can have too much of a good thing. In nature nuts would be presented in shells and take a little work to eat so you couldn’t mindlessly eat them, whereas today they’re presented ready-to-eat. They should be eaten in small portions due to their high calorie content.
Plant-based diets help with weight loss through their ability to reduce energy intake, and increase the thermic effect of food. They help you consume fewer calories, whilst burning more, without having to carefully count calories, or increase your physical activity. Plant-based diets are high in fiber, as well as nutrients, making you feel fuller for longer, while reducing hunger and cravings during the day. This creates long-lasting effects for your weight and overall health.
Whilst focusing on diet quality and healthy food consumption is most important for our health, it's good to be mindful of those high-calorie healthy foods like nuts and avocados when trying to lose weight, as well as processed vegan food and added oils. Processed foods are rarely a good choice, no matter which diet you choose to follow.
Choose a whole-food plant-based diet and live happier, healthier, and lighter for the long-run.
1. Fryar CD, Carroll MD, Afful J. Prevalence of overweight, obesity, and severe obesity among adults aged 20 and over: United States, 1960–1962 through 2017–2018. NCHS Health E-Stats. 2020;1–7.
2. Hall KD, Guo J, Courville AB, Boring J, Brychta R, Chen KY, et al. Effect of a plant-based, low-fat diet versus an animal-based, ketogenic diet on ad libitum energy intake. Nat Med. 2021 Feb;27(2):344–53.
3. Barnard ND, Alwarith J, Rembert E, Brandon L, Nguyen M, Goergen A, et al. A Mediterranean Diet and Low-Fat Vegan Diet to Improve Body Weight and Cardiometabolic Risk Factors: A Randomized, Cross-over Trial. J Am Nutr Assoc. 2022 Feb 17;41(2):127–39.
4. Tomova A, Bukovsky I, Rembert E, Yonas W, Alwarith J, Barnard ND, et al. The Effects of Vegetarian and Vegan Diets on Gut Microbiota. Front Nutr. 2019 Apr 17;6:47.
5. Klementova M, Thieme L, Haluzik M, Pavlovicova R, Hill M, Pelikanova T, et al. A Plant-Based Meal Increases Gastrointestinal Hormones and Satiety More Than an Energy- and Macronutrient-Matched Processed-Meat Meal in T2D, Obese, and Healthy Men: A Three-Group Randomized Crossover Study. Nutrients. 2019 Jan 12;11(1):157.
6. Calcagno M, Kahleova H, Alwarith J, Burgess NN, Flores RA, Busta ML, et al. The Thermic Effect of Food: A Review. J Am Coll Nutr. 2019 Aug 18;38(6):547–51.
7. Barnard ND, Scialli AR, Turner-McGrievy G, Lanou AJ, Glass J. The effects of a low-fat, plant-based dietary intervention on body weight, metabolism, and insulin sensitivity. Am J Med. 2005 Sep;118(9):991–7.
8. Kahleova H, Petersen KF, Shulman GI, Alwarith J, Rembert E, Tura A, et al. Effect of a Low-Fat Vegan Diet on Body Weight, Insulin Sensitivity, Postprandial Metabolism, and Intramyocellular and Hepatocellular Lipid Levels in Overweight Adults: A Randomized Clinical Trial. JAMA Netw Open. 2020 Nov 30;3(11):e2025454.
9. Najjar, Feresin. Plant-Based Diets in the Reduction of Body Fat: Physiological Effects and Biochemical Insights. Nutrients. 2019 Nov 8;11(11):2712.
10. Tonstad S, Butler T, Yan R, Fraser GE. Type of Vegetarian Diet, Body Weight, and Prevalence of Type 2 Diabetes. Diabetes Care. 2009 May 1;32(5):791–6.
11. Turner-McGrievy GM, Barnard ND, Scialli AR. A Two-Year Randomized Weight Loss Trial Comparing a Vegan Diet to a More Moderate Low-Fat Diet*. Obesity. 2007 Sep;15(9):2276–81.
12. Turner-McGrievy GM, Davidson CR, Wingard EE, Wilcox S, Frongillo EA. Comparative effectiveness of plant-based diets for weight loss: A randomized controlled trial of five different diets. Nutrition. 2015 Feb;31(2):350–8.
13. Wright N, Wilson L, Smith M, Duncan B, McHugh P. The BROAD study: A randomised controlled trial using a whole food plant-based diet in the community for obesity, ischaemic heart disease or diabetes. Nutr Diabetes. 2017 Mar;7(3):e256–e256.
14. Orlich MJ, Fraser GE. Vegetarian diets in the Adventist Health Study 2: a review of initial published findings. Am J Clin Nutr. 2014 Jul 1;100(suppl_1):353S-358S.