Plant-Based Diet for Weight Loss
Feel satisfied while eating fewer calories.
9/11/20236 min read
There are countless ways to “diet,” but not many ways of eating that are truly sustainable for the long haul. Too many have faced the ups and downs of yo-yo dieting, only to feel discouraged and hopeless. One approach worked for a time, perhaps, but it didn’t stick (or wasn’t even meant to). As a result, the question many are asking is: How can you lose weight and keep it off?
Well, to start, let’s consider a diet that is defined as a way of eating, not just a short-term list of dos and don’ts that delivers results that won’t last.
It’s no secret that weight loss requires a calorie deficit. Meaning, in order to lose weight, one must use or “metabolize” more energy than she consumes. There are many ways to achieve this, but sustainable weight loss is only going to happen when the dietary pattern one follows leaves her feeling satisfied, not restricted and in want.
What if you could eat until you felt full and get to a healthy body weight? What if you could embrace and enjoy food rather than focusing on exclusion and restriction?
Enter plant-based eating. This doesn’t necessarily have to be plant-exclusive, though it can be. Aim for 85% or more of your daily caloric intake to come from plants, with most of those to come from whole plant foods with a low and medium calorie density, and you’ll be well on your way.
How does plant-based eating achieve weight loss?
In a nutshell: satiety.
Satiety is essentially the opposite of hunger. It is the feeling of being satisfied, even full, and not needing any more food at the time. Being satiated doesn’t mean that you should feel overfull; rather, it is the feeling of having had enough and no longer being hungry.
So, why plants? It is easier to feel satiated on fewer calories when eating whole plants.
Plant foods are terrific at promoting satiety, especially fresh vegetables and fruits, as well as legumes and whole grains. These foods typically have a high water content, contain fiber, and require a decent amount of chewing, all of which promote satiety.
However, just because something is made from plants does not necessarily make it satiety promoting. Take a bag of potato chips, for example. Not only are these notably low in water and fiber and require very little chewing, they are also loaded with fat and salt, two key players in making us want to eat more rather than encouraging us to slow down or stop.
On the other hand, think of a big salad. This requires a lot of chewing—and time—to work your way through. If it contains a variety of good toppings, including good sources of fiber and protein—say, chickpeas, tomatoes, walnuts, and even some cooked wheat berries—not only will the chewing and water content help you feel full, the protein and fiber will help keep you feeling satisfied. Grain bowls, soups, stir-fries, and porridges are other good examples.
Which plants should I eat?
We already covered that potato chips should not be a staple in this dietary approach. Above, the concept of calorie density came up. What is calorie density? How can paying attention to this help you with sustainable weight loss?
In essence, calorie density has to do with how many calories are in a given amount of food (by weight).
For instance, kale, sweet potatoes, and fresh apples have a low calorie density compared to black beans and whole wheat bread, which have a medium calorie density. Foods with a high calorie density are typically high in fat, such as nuts and seeds. This doesn’t make such foods “bad”; rather, it just helps determine which foods should make up the bulk of your plate: mostly foods with a low calorie density, followed by some foods with a medium density, and lastly a small amount of those with a high density.[1]
Most fresh fruits and vegetables have a low calorie density. Exceptions include things like avocados and dried fruit, which, while certainly good in moderation, should be limited if weight loss is the goal. Legumes and whole grains have a medium calorie density. Nuts and seeds have a high calorie density, and because they are low in water content, they can be easy to overeat. It is certainly preferable to include whole sources of good fats rather than oils (e.g., using walnuts or pumpkin seeds on a salad—or even whole olives—rather than olive oil), but, as with avocado and dried fruits, consume these mindfully in smaller quantities if you’re aiming for weight loss.
But what about keto?
Can’t someone lose weight on a ketogenic diet?
Yes. Many people have.
There are lots of people promoting and trying out various versions of the keto diet these days, and many people experience some level of success with weight loss. However, in addition to there not being much long-term data on ketogenic diets as far as health outcomes, there has been some enlightening research showing that plant-based approaches to weight may promote more fat loss than keto diets.
Keto vs. Plant-Based—Put to the Test
A 2021 study by Kevin Hall and colleagues desired to look at whether a keto diet would reduce ad libitum[2] energy intake as compared to a low-fat, high-carbohydrate diet.[3] The diets put head to head were both minimally processed and thus consisted of mostly whole foods, but one was animal-based keto and the other was plant based and low fat. The participants spent two weeks (14 days) on one diet, and two weeks on the other. The results were very interesting.[4]
While on the animal-based diet, participants lost more weight in the first seven days, but the second seven days showed a slowing of their weight loss nearing a plateau in the last four days. Contrariwise, the plant-based diet produced more modest weight loss during the first week followed by a slight increase in continued weight lost during the second week. When we dive in even further, we can see the type of weight that was lost on either diet. While eating the animal-based diet, most of the weight lost was fat-free mass (meaning, water and muscle). While eating the plant-based diet, they lost more fat over the two-week span.
This study just keeps getting more interesting. The subjects were asked about their levels of hunger, satisfaction, and fullness on either diet, and these results were nearly equal across the board. But ... wait for it ... when eating the plant-based diet, on average, they ate about 700 fewer calories per day. That’s crazy! Can you imagine feeling just as satisfied on 700 less calories each day? That’s the beauty of eating mostly whole plant foods.
Granted, this study only had participants eat each diet for two weeks. But there are certainly some takeaways to help direct us in choosing what kind of dietary pattern is most sustainable if weight loss is the goal:
The plant-based approach enabled participants to feel just as satisfied by their meals while eating about 700 calories less than when eating keto.
While eating keto, they did lose weight, but predominantly water and muscle mass rather than fat.
While eating plant-based, participants lost more fat.
It is helpful to close by noting that a plant-based dietary pattern that is sustainable for the long haul should not feel restrictive and does not have to be vegan. As long as 85% or more of your energy is coming from whole plants and the majority of those are low and medium in their calorie densities, you are likely to have a much better shot at sustainable, long-term weight loss while eating foods that are delicious and satisfying—and nutritious to boot.
Finally, the joy of a plant-based way of eating is that it encourages celebrating abundance rather than focusing on what you “can’t” eat.
Notes:
[1] Oils have a very high calorie density—they are typically pure fat, and fat contains 9 calories per gram compared to 4 calories per gram for both carbohydrates and protein. Use of oils is best kept to a minimum if your goal is to lose weight.
[2] Meaning, essentially, as much or as often as necessary or desired.
[3] Study on PubMed: https://pubmed.ncbi.nlm.nih.gov/33479499/.
[4] Simon Hill provides a helpful interpretation of this study in a downloadable resource here: https://theproof.com/drb/. There is also a video by Chris MacAskill looking at this study on his Plant Chompers YouTube channel here: https://www.youtube.com/watch?v=zOAapJo9cE0&t=1218s.
Photo courtesy of Caroline Green on Unsplash.
