Many people are inspired to try a wholefood plant-based diet by the plethora of anecdotes about the effortless weight loss facilitated by this way of eating. Documentaries such as Forks Over Knives, Eating You Alive and What the Health, along with countless blogs and podcast episodes, feature remarkable true stories of people who have battled with their weight their whole lives, until finally they discover a wholefood plant-based diet, and voilà – their excess kilos melt away, without them needing to exercise like maniacs or eat tiny portions.
The oft-repeated mantra is
“I can eat as much as I like on this diet, and still lose weight!”
While this is true for many people (especially men), there is a sizeable minority (primarily women, especially those with a history of dieting and/or being significantly overweight for a prolonged period) who require more fine-tuning of the basic wholefood plant-based diet plan in order to achieve and maintain a healthy weight.
I receive so many questions about this vexed issue that I’m running a webinar called ‘Optimising Weight Loss on a Plant-Based Diet’ on Tuesday 27 February, as part of my EmpowerEd health and nutrition education program.
One of the topics I’m covering in the webinar is the effect of salt on food intake and weight. Salt is a divisive issue among leading advocates of a plant-based diet. Some, including Alan Goldhamer and Joel Fuhrman, advocate total abstinence from added salt, while others, including John McDougall and Pam Popper, argue that stringent salt restriction is unnecessary and that adding salt to wholefood plant-based meals may increase compliance by making ‘new’ foods more palatable.
But it’s this very palatability that salt lends to food, that may make losing weight and keeping it off extraordinarily difficult for some people.
Researchers at the Centre for Advanced Sensory Science in Victoria’s Deakin University conducted a fascinating study which examined the effects of varying the amount of salt and fat in an otherwise standardised meal of pasta with sauce, on the amount of food that people ate, and how palatable and satiating it was to them (i.e. how full they felt afterwards, and how long it took them to feel hungry again).
They recruited 16 men and 32 women, aged between 18 and 54, and ranging from slightly underweight (body mass index [BMI] 17.8) to obese (BMI 34.4). Participants were first assessed for fat taste sensitivity, which is the ability to detect the taste of fat in food. Fat sensitivity is a biological mechanism that tells us when we’ve taken in enough fat and should stop eating. Overweight people have lower fat taste sensitivity, meaning that they don’t get the message that they’ve eaten enough fat, until they’ve eaten too much.
People with high fat taste sensitivity find the taste of fat repulsive and tend to eat less of a food or meal that is high in fat. Given the energy density of fat (9 calories/38 kilojoules per gram, vs the 4 calories/17 kilojoules per gram in carbohydrate and protein), having high fat taste sensitivity is clearly a plus for weight loss! (Fortunately, fat taste sensitivity can be restored in those with low sensitivity, by reducing the amount of fat in their diet for as little as 6 weeks.)
After their fat taste sensitivity was determined, participants were fed different versions of the test meal over 4 lunchtime sessions: low-salt and low-fat, low salt and high-fat, high-salt and low-fat, and high-salt and high-fat.
The results were eye-opening:
- When people were given the high-salt version of the pasta dish, they ate 11% more food and energy (kilojoules/calories), regardless of whether they were eating the high-fat or low-fat version. Put simply, salt made them eat more.
- Although people didn’t eat a larger quantity of the high-fat meal than the low-fat meal, they still ended up eating 60% more kilojoules/calories, simply because the high-fat meal was so much more energy-dense than the low-fat meal.
- People with high fat taste sensitivity ate less of the high-fat meal, as predicted… except when it had added salt. The salt overrode their fat taste sensitivity, causing them to eat more of a food they would normally have disliked
The researchers concluded:
“The results suggest that salt promotes passive overconsumption of energy in adults and that salt may override fat-mediated satiation in individuals who are sensitive to the taste of fat.”
The implications of this study are rather obvious and very confronting. Habitually eating 11% more calories/kilojoules than you otherwise would, because there was salt added to your meal, is clearly counterproductive to weight loss. And having your fat taste sensitivity overridden by salt, so that you eat more energy-dense fat-rich foods than you would if there was no salt added to those foods, just piles on the damage.
Of course, the food industry has long been aware of the effect of salt on people’s appetite and food consumption, as investigative journalist Michael Moss detailed in his riveting exposé Salt Sugar Fat. Without salt, popular snack foods such as chips and crackers are utterly unappealing. Even sweet foods can be made more addictive with the addition of salt – hence the current craze for salted caramel chocolate and ice cream.
Yet even when I explain the science of salt, overconsumption and weight gain to clients, many are reluctant to break up with salt. “I can’t eat potatoes/tomatoes/whatever without salt!” they insist. I reassure them that although their food will taste bland at first, their taste buds will calibrate within 3-4 weeks, after which they’ll be able to detect even low concentrations of salt in food.
And without fail, clients return after a month or so and report that for the first couple of weeks they hated me SOOOO much because their food tasted terribly bland, and then, perhaps for the first time in their whole lives, they began to actually taste their food. “It’s amazing – I never knew what a tomato tasted like before!” must be one of the most common things I hear!
Clients also report that after reducing their salt intake, they begin to find processed and restaurant foods quite repulsive. And most importantly, many also notice that they’re spontaneously eating less food, without consciously trying to restrict.
Of course, dumping salt is not a magic bullet when it comes to weight loss, which is a complex process affected by a plethora of physical and psychological factors. But since there is no down side to reducing your salt intake (after all, humans evolved on a diet containing only one-tenth of our current average sodium intake), why not give it a try? Herbs, spices, lemon and lime juice can be used to enhance the flavour of food, and unlike salt, they offer additional benefits such as antioxidant and anti-inflammatory phytochemicals… without driving you to overeat.
If you would like to participate in the ‘Optimising Weight Loss on a Plant-Based Diet’ webinar, or watch the recording afterward, redeem your free 1-month trial of EmpowerEd membership and access details will be sent to you.
For personalised help with your weight loss goals, apply for a Roadmap to Optimal Health Consultation today.
Leave A Response