Weight Management

Maintaining weight is harder than losing it. Unlike fad diets, lifestyle interventions can help you to maintain a healthy weight years, if not decades.

Obesity has reached epidemic proportions around the world.

In the US, over 70% of adults are overweight or obese. 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.  

Obesity is a major risk factor for type 2 diabetes, cardiovascular disease and other chronic conditions. It also leaves people to struggle with daily tasks, as well as feeling uncomfortable in their own skin. 

Clearly, what we’re currently doing to fix the problem isn’t working. Calorie restriction is not a long-term solution, and neither are most fad diets that make up the multi-billion dollar industry.  

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. Here we discuss the evidence and the mechanisms behind these claims. 

What is obesity?

Obesity is defined as excess body fat that’s a risk to your health. It’s based on your BMI, which is a measure of your weight (kg) divided by your height squared (m2), and is split into these categories:

  • Underweight, <18.5
  • Normal BMI, 18.5 - 24.9
  • Overweight, >24.9
  • Obese, > 30
  • Severly obese, > 40

How good is BMI as a measure of my health?

BMI isn’t perfect, and should be taken with a pinch of salt. 

It doesn't specifically determine excess fat mass, as it can’t distinguish between body fat and muscle mass 1. That means it can overestimate or underestimate fatness due to factors like age, muscle mass, and ethnicity 2

BMI also can’t measure where body fat is carried. Fat carried around our middle can pose a bigger health risk than when carried elsewhere, like our arms or thighs. Some people have a normal BMI but carry too much fat for their size, so may have a false sense of security regarding their health. Conversely, you can have an overweight BMI but be fit and have a healthy metabolic profile 3.

Other measurements that may be a better indicator of body fat and its risk to health are waist circumference, and waist/hip ratio 4

Waist circumference can determine abdominal obesity (and an increased risk of diabetes and heart disease) at the following levels 5:

  • Men, over 102 cm (40 inches)
  • Women, over 88 cm (35 inches)

How does my weight affect my health?

Being overweight and carrying too much body fat is a major risk factor for non-communicable diseases. It can increase your risk of cardiovascular disease, several cancer types, type 2 diabetes, chronic kidney disease, dementia, and osteoarthritis. It can also shorten life expectancy and lower your quality of life 6. Being obese can affect someone’s ability to carry out daily tasks easily. Despite the risks associated with being overweight, simple changes to your diet lifestyle can have a big impact.   

What are the causes of obesity?

Consuming more calories than you burn is the basic, physiological cause of obesity. Our diet is the main determinant of this, and of weight gain. Western diets are high in processed and animal-derived foods and are implicated in the development of obesity. For example, red meat, poultry, and processed meat are direct causes of weight gain 7

Despite diet being the main cause, the contributing factors to becoming obese are complex, including genetic, environmental, psychological, social, and economic reasons 8. Obesity isn’t always treated like other diseases, and people aren’t always given the support they need. Many may have simply been told to ‘eat less’, but this is not how you cure obesity in the long-run. 

Lower physical activity levels also contribute to weight gain. We live less active lives than previous generations as behaviors have shifted to be more sedentary. Many of us now drive to work, sit at a desk all day, and watch TV or use the internet in our free time 8. Lack of sleep is also associated with a higher BMI 9, and sleep restriction can result in increased hunger hormones and a bigger appetite 10. Stress, medications, and various health conditions also contribute to weight gain. 

Treatments for obesity 

The first line of treatment for obesity is diet and lifestyle changes, including making healthier food choices, reducing alcohol intake, and increasing physical activity. 

Bariatric surgery can help people lose large amounts of weight that they’ve otherwise struggled to shift. However, this involves invasive surgery and the risk of several complications 2

Several drug treatments are available, and these aren’t always that effective for weight loss, and often are limited by side effects, or the tendency of patients to relapse post-therapy 11

There are so many calorie-restrictive, food-group restrictive, and liquid diets for weight loss online. While these can help weight-loss in the short-term, they’re not sustainable ways to create long-term change. 

Is there a long-term solution to weight loss without negative side effects?

Yes, a whole-food plant-based (WFPB) diet, that promotes fruits, vegetables, whole grains, and legumes, and minimizes processed foods and animal products, provides a way to achieve meaningful, long-term weight loss. Studies looking at plant-based diets, either vegetarian, vegan, or WFPB, have consistently shown that they are effective weight loss tools, even without added physical activity or restrictions on calorie intake. 

Obesity is uncommon in individuals eating a plant-based diet. In the Adventist Health Study 2, those on a plant-based diet had the lowest BMI compared to all other dietary patterns. The study showed that the more animal products in the diet, the higher the BMI. Even those who were semi-vegetarian had a lower BMI on average than non-vegetarians 12 13

This is  great news if you’re looking to prevent weight gain, but what about if you’re looking to lose weight, can a plant-based diet help?

The simple answer is yes. 

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 14. The same was seen in overweight men, where weight loss on the plant-based diet was significantly greater than the omnivorous, semi-vegetarian, and pesco-vegetarian diets 15

A recent community study provided participants with skills, namely cooking skills, to encourage behavior change and the transition to a WFPB diet. The WFPB diet group had a significantly greater reduction in weight and BMI, which was sustained, compared to the control group provided with normal care alone 16. This study is a unique example given its real world nature. The doctors provided skills and education, like we do at Mora, to participants struggling with their weight, allowing them to make their own WFPB diet food choices, and it reaped huge benefits. If these people can do it, anyone can. 

For many, losing weight is easier than keeping it off in the long run. That’s why an effective weight loss plan has to be something that’s sustainable, and allows you to continue enjoying your food. That’s precisely what a plant-based diet can do, and these studies show that in the years following, both the plant-based diet and weight loss were maintained. One study looking at the long-term benefits of a plant-based diet found that each additional year on a vegan diet lowered the risk of obesity by 7% 17.

Even with a similar caloric intake, plant-based diets result in more weight loss than other dietary patterns 18. Thus, what you eat matters, as well as the number of calories. Can you guess which foods are associated with weight loss and weight gain? That’s right - fruits, vegetables, whole grains, and nuts are all associated with weight loss, whereas unprocessed red meats, processed meats, potato chips and sugar sweetened-beverages all increase weight gain 19

How does a plant-based diet help with weight loss?

There are several mechanisms behind plant-based diets helping with weight loss:

  1. Reduced energy density. Plant foods are low in calories because of their high fiber and water content 20. This means they’re less energy dense than animal-derived foods. For example, 100g of chicken has 6 times the amount of calories compared to 100g of broccoli. Fiber is the dietary key to weight loss, it bulks up food without adding calories, making meals more satiating and keeping you fuller for longer. And it’s only found in plant foods! The overall plant-based dietary pattern therefore contains fewer calories without having to restrict portion size or feel hungry 21 22
  2. Reduced fat intake on a WFPB diet. When following a plant-based diet without added oils, fat typically comprises 7-15% of total energy consumed. This can result in a greater loss of body fat, as less of what we eat is stored as fat, and fat stores can start to get used up and disappear 20.
  3. 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 the calories we burn daily is from breaking down and utilizing our food, this is known as the thermic effect of food. 23. Research shows us that eating a plant-based meal can increase the number of calories burned, compared to an omnivorous meal 24 20. The lower fat content of most plant-based meals allows the mitochondria in our cells to work more efficiently, increasing the calories burned. A plant-based diet also improves insulin sensitivity, due to less fat accumulating in the liver and muscle cells, which can partly explain this 25 20 26
  4. Plant foods are better at regulating our appetite hormones. A recent study compared a processed-meat and cheese meal to a vegan meal with tofu on appetite hormones. The vegan meal increased levels of gut satiety hormones glucagon-like peptide-1 (GLP-1), amylin, and peptide YY (PYY), and feelings of satiety, significantly more than the processed meal, in healthy, obese, and diabetic men. These hormones help to keep weight down, regulate blood sugar and keep us fuller for longer 27.
  5. Better health of the gut microbiome. Our gut microbiome is important for our overall health, including maintaining a healthy weight. One type of gut bacteria, Bacteroidetes, are associated with lower weight, and another type, Firmicutes, are associated with obesity, because they increase calories absorbed from the diet 28. A plant based diet, which is high in fiber, can increase bacteroidetes and reduce firmicutes, which helps to promote weight loss as fewer calories are extracted from the diet 29

Summary 

Plant-based diets are an attractive and sustainable way to lose weight and prevent weight gain. 

They’re a sustainable way to keep the weight off for good, which is the more important outcome for long term health. An appeal of using a WFPB diet for weight loss, is that you don’t have to track your calories, allowing for more freedom with your meals; you won’t feel hungry or like you’re restricting entire food groups. 

Forget the restrictive diet programmes and choose to live healthy and happy on a WFPB diet, where the plethora of plant foods and ways to eat them is endless. Focus on whole, plant-foods that are full of fiber, rather than processed foods or animal products. This helps to keep you fuller for longer, keeps the levels of saturated fat down, and allows your gut microbiome to thrive and further regulate your weight.

A plant-based diet sets you up for success, not failure, on your weight loss journey. 

Making these changes can be hard at first. Here at Mora Medical, our medical team supports and encourages behavior change and provides you with all the right tools to live a WFPB lifestyle and maintain a healthy weight. 

References 

1. Rothman, K. J. BMI-related errors in the measurement of obesity. Int. J. Obes. 32, S56–S59 (2008).

2. Ruban, A., Stoenchev, K., Ashrafian, H. & Teare, J. Current treatments for obesity. Clin. Med. 19, 205–212 (2019).

3. Roberts, C. K. et al. Strength Fitness and Body Weight Status on Markers of Cardiometabolic Health. Med. Sci. Sports Exerc. 47, 1211–1218 (2015).

4. Huxley, R., Mendis, S., Zheleznyakov, E., Reddy, S. & Chan, J. Body mass index, waist circumference and waist:hip ratio as predictors of cardiovascular risk—a review of the literature. Eur. J. Clin. Nutr. 64, 16–22 (2010).

5. National Institutes of Health. Managing Overweight and Obesity in Adults:  Systematic Evidence Review from the Obesity Expert Panel. (2013).

6. Blüher, M. Obesity: global epidemiology and pathogenesis. Nat. Rev. Endocrinol. 15, 288–298 (2019).

7. Vergnaud, A.-C. et al. Meat consumption and prospective weight change in participants of the EPIC-PANACEA study. Am. J. Clin. Nutr. 92, 398–407 (2010).

8. Wright, S. M. & Aronne, L. J. Causes of obesity. Abdom. Radiol. 37, 730–732 (2012).

9. Gangwisch, J. E., Malaspina, D., Boden-Albala, B. & Heymsfield, S. B. Inadequate Sleep as a Risk Factor for Obesity: Analyses of the NHANES I. Sleep 28, 1289–1296 (2005).

10. Spiegel, K., Tasali, E., Penev, P. & Cauter, E. V. Brief Communication: Sleep Curtailment in Healthy Young Men Is Associated with Decreased Leptin Levels, Elevated Ghrelin Levels, and Increased Hunger and Appetite. Ann. Intern. Med. 141, 846 (2004).

11. Williams, D. M., Nawaz, A. & Evans, M. Drug Therapy in Obesity: A Review of Current and Emerging Treatments. Diabetes Ther. 11, 1199–1216 (2020).

12. Tonstad, S., Butler, T., Yan, R. & Fraser, G. E. Type of Vegetarian Diet, Body Weight, and Prevalence of Type 2 Diabetes. Diabetes Care 32, 791–796 (2009).

13. Orlich, M. J. & Fraser, G. E. Vegetarian diets in the Adventist Health Study 2: a review of initial published findings. Am. J. Clin. Nutr. 100, 353S-358S (2014).

14. Turner-McGrievy, G. M., Barnard, N. D. & Scialli, A. R. A Two-Year Randomized Weight Loss Trial Comparing a Vegan Diet to a More Moderate Low-Fat Diet*. Obesity 15, 2276–2281 (2007).

15. Turner-McGrievy, G. M., Davidson, C. R., Wingard, E. E., Wilcox, S. & Frongillo, E. A. Comparative effectiveness of plant-based diets for weight loss: A randomized controlled trial of five different diets. Nutrition 31, 350–358 (2015).

16. 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 7, e256–e256 (2017).

17. Chiu, Y.-F. et al. Cross-sectional and longitudinal comparisons of metabolic profiles between vegetarian and non-vegetarian subjects: a matched cohort study. Br. J. Nutr. 114, 1313–1320 (2015).

18. Medawar, E., Huhn, S., Villringer, A. & Veronica Witte, A. The effects of plant-based diets on the body and the brain: a systematic review. Transl. Psychiatry 9, 226 (2019).

19. Mozaffarian, D., Hao, T., Rimm, E. B., Willett, W. C. & Hu, F. B. Changes in Diet and Lifestyle and Long-Term Weight Gain in Women and Men. N. Engl. J. Med. 364, 2392–2404 (2011).

20. Kahleova, H. 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 3, e2025454 (2020).

21. Hall, K. D. et al. Effect of a plant-based, low-fat diet versus an animal-based, ketogenic diet on ad libitum energy intake. Nat. Med. 27, 344–353 (2021).

22. Barnard, N. D. 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. 41, 127–139 (2022).

23. Calcagno, M. et al. The Thermic Effect of Food: A Review. J. Am. Coll. Nutr. 38, 547–551 (2019).

24. Barnard, N. D., Scialli, A. R., Turner-McGrievy, G., Lanou, A. J. & Glass, J. The effects of a low-fat, plant-based dietary intervention on body weight, metabolism, and insulin sensitivity. Am. J. Med. 118, 991–997 (2005).

25. Goff, L. M., Bell, J. D., So, P.-W., Dornhorst, A. & Frost, G. S. Veganism and its relationship with insulin resistance and intramyocellular lipid. Eur. J. Clin. Nutr. 59, 291–298 (2005).

26. Najjar & Feresin. Plant-Based Diets in the Reduction of Body Fat: Physiological Effects and Biochemical Insights. Nutrients 11, 2712 (2019).

27. Klementova, M. 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 11, 157 (2019).

28. Ley, R. E., Turnbaugh, P. J., Klein, S. & Gordon, J. I. Human gut microbes associated with obesity. Nature 444, 1022–1023 (2006).

29. Tomova, A. et al. The Effects of Vegetarian and Vegan Diets on Gut Microbiota. Front. Nutr. 6, 47 (2019).

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