“Veges first, carbs last”: the chance discovery that could revolutionise the way we eat and help fight obesity, diabetes and heart disease. By Jane Clifton.
For someone whose research career briefly hit the doldrums after emergent DNA science failed to answer her burning questions, Jessie Inchauspé's enthusiasm bounced back on a surprisingly simple concept: eat your veges first.
The advice that everyone's great-grandmother might have doled out is hardly the holy grail the young biochemist had set out to find to elucidate the human condition. But her research on the effect of eating patterns has brought promising new insights into how to manage a range of deadly conditions, notably obesity and diabetes, from their ground zero: blood sugar, or glucose.
Inspired by her own experience using a personal blood sugar monitor, she has aggregated recent clinical trials into strategies for controlling blood glucose spikes – known to be one of the golden keys to controlling obesity, diabetes and other metabolic disorders. Her book, Glucose Revolution, posits a three-step order-of-eating system: in simple terms, vegetables first, then proteins, and carbohydrates last.
Inchauspé had been working for a medico-science research company in Silicon Valley when, as an incidental staff benefit, her employers decided to test a then-novel bit of kit: a digital monitor that tracked glucose via a tiny filament inserted in the arm. Having spiralled through the customary range of eating styles typical of her then twenty-something age group – from strict vegan to keto to what-the-hell junk food – she became fascinated by how different foods affected her blood sugar.
She noticed her better energy and mood levels coincided with prolonged periods of stable glucose. Then she twigged that the order in which she ate certain food groups could have a dramatic effect on that glucose stability.
If she ate vegetables first, then protein and left the carbohydrates in any meal until last, her blood sugar remained much more stable than if she reversed the order. If she ate only carbs, she experienced spikes that quickly sapped her energy.
This may be one of those rare instances when something that sounds too good to be true is nevertheless true.
“When you eat something like a salad, the fibre in those veges forms a physical barrier, like a mesh, in your stomach. That slows down the digestion of whatever you eat next. So everything you eat is released into the bloodstream more gradually, and that’s good news,” Inchauspé says.
"What I love about this is that it's not a matter for debate. It's a fact. You can't argue with the science! And, look, you don't need a glucose monitor. We know enough about the effects of different foods so that anyone can eat this way and get good results controlling their blood sugar."
The science behind her book is, indeed, well established. As has been known for many decades – and popularised in the 1980s by the F-Plan high-fibre diet craze – fibre is not digested, but passes through the digestive system intact. This “roughage”, as our nanas used to call it, has numerous benefits besides “keeping us regular” – a special bonus being, as Inchauspé puts it, that it “blocks the sink” by staying in the stomach longer than other types of food. If enough of it lands in the stomach first in a meal, it slows digestion of everything else – both as a physical barrier and as an inhibitor of alpha amylase, the enzyme that breaks starch down into glucose.
Protein also leaves the stomach relatively slowly and keeps people feeling fuller for longer, which is why diabetes and obesity specialists recommend a serving of lean protein as a part of every meal.
As the "expert" dogma against carbohydrates religiously preaches, pasta, bread, root vegetables and the like hit the metabolic ground running, causing rapid blood sugar spikes. Spikes above a certain level cause a bodily chain of command that can, over time, devastate a person's health. But anything that ankle-taps glucose's absorption speed is apt to be protective.
Waves of diet literature have also cribbed from the diabetes community in championing low-glycaemic-index foods that cause more moderate release of blood sugar and insulin. These are often fibre-rich, low-sugar foods.
Unlucky Break
Inchauspé had at first devoted her career to studying DNA, believing it would give her new insights into what made people tick. Her quest was very personal. As a result of a silly dare at 19, she had jumped into a waterfall, landed badly and broken her back. Extensive surgery eventually restored her mobility, but she experienced persistent physical and emotional problems for years, which she struggled to understand or get effective treatment for. “I was convinced DNA would give me the answers I was looking for, but it turned out … it’s not that simple.”
She says she's not sure where science would have taken her next had the serendipitous work perk not led her to experience how drastically glucose levels could make or break people's health.
At first glance, sceptics might misassociate Inchauspé's eating system with last century's intermittent fads under the "food-combining" umbrella. These erroneously claimed that different food types should be eaten hours apart as, say, fruit and meat interfered with one another's digestion, leaving dangerous fermentation to produce "toxins" in our intestines. In vain did doctors and scientists point out that stomach acid was a pretty efficient dispatcher of all-comers, and the liver was something of an expert at removing toxins.
Further scepticism may arise from this being "yet another" diet book and business empire. Inchauspé now works full-time between the United States and Paris on her "Glucose Goddess" business, comprising an interactive website and the book. She'll be visiting New Zealand to promote them later this year.
However, her work has been endorsed by health science populist Dr Michael Mosley and chimes with blood glucose monitoring work pioneered by genetic epidemiologist Dr Tim Spector in conjunction with Harvard and several other universities. Spector’s work, via the Zoe Programme, a 400,000-participant nutritional study, focuses mostly on gut health and how to reduce the inflammatory effect of foods, but it places glucose management at ground zero of healthy metabolism – the process of converting what we consume into energy.
The Sugar Rush
Glucose is a very recent gargoyle factor in human health. For most of history, we hardly ever got any sugar. Apart from honey, sugars were seasonal and scarce, coming from fruits and vegetables, typically in tiny portions.
It wasn't until the widespread availability of table sugar in the 1700s that humans began to eat simple sugars regularly – now an average 42kg per person a year. Recognising sugar as a highly efficient, but – until now – scarce source of fuel, the human brain evolved to strongly attract people to it, by rewarding its consumption with the "pleasure" neuro-transmitter, dopamine. Alas, to modern humans, this has become a maladaptive feedback loop.
The body can do without carbs, making its own glucose by metabolising fat and protein. Some mammals, including dolphins and Arctic circle settlements, have long lived healthily carb-free – the "aha!" factor behind the Atkins and Keto diets. But these are heavily restrictive diets, and not a fix for the fact that the ready modern supply of highly palatable sugared foods is going into bodies not yet evolved to cope with them.
The science behind how the “blocked sink” stomach method could help is a fascinating roil of enzymes, hormones and cells. As glucose from carbs enters the bloodstream, microscopic cell organelles – mitochondria – marshal to make it available as fuel. Inchauspé playfully likens mitochondria’s work to that of a stoker on a steam train with a potentially ungovernable supply of coal. The “train” can use only a certain amount of fuel at once, and what’s left over from that double-helping of pavlova causes several problems.
Over time, if constantly overloaded, mitochondria's efficiency deteriorates, so the body's cells don't get enough fuel to function optimally. Worse, glucose overload provokes a rampage of free radicals – unstable, highly reactive atoms that can damage cells, modify DNA and even help cause cancer.
The body can effectively detoxify these molecules, but constant glucose spikes overtax and unbalance its defence mechanisms. This state of weakened defences is oxidative stress, the launching pad for much of what we dread most: heart disease, type 2 diabetes, cognitive decline and accelerated ageing.
In oxidative stress, the body can respond as though it's being attacked by an infection or contaminant, and in recruiting its immune defence system, cause further damage through inflammation or tissue swelling, in a sort of misguided overkill reaction. The World Health Organisation ranks inflammation the single biggest threat to human health.
Naturally, a Bruce Willis-style action hero is combating this global enemy, in the form of insulin from the pancreas. Insulin diverts any excess glucose safely into the liver, where it can be converted into glycogen and stored until it's needed for energy later. But the liver can store only so much – two large McDonald's fries-worth, to be precise, or 100g. If there's more, the insulin directs it next to the muscles, which can hold up to 400g. But anything over that amount has to be converted into fat.
This isn't the end of the world, necessarily, but there's a real Bond villain to factor in next: fructose. Fructose is a simple sugar, derived most notoriously from the ubiquitous but strongly medically denounced food additive corn syrup. Fructose's super-power is that it can only ever be stored as fat. That's why a diet too high in sugary foods bypasses all the body's safe, healthy glucose-storage options and goes straight into blubber – in the worst way. Fructose-created fat has a propensity to accumulate in the liver and to turn into low-density lipoprotein – "bad" cholesterol – which clogs arteries.
The bottom line is fat can be burnt, and “bad” fat deterred, only if the body has a low, steady blood sugar count.
Practical Fishhooks
Practitioners at the coalface of obesity and metabolic disorders are a tough crowd, schooled by repeated diet fad hokum to be sceptical about new eating systems. Many will recoil at Inchauspé's frequent use of the word “hack” – as in shortcut or trick – with respect to blood sugar management.
But although those the Listener consulted saw some practical fishhooks with her eating advice, they were guardedly positive about its fundamentals. They agree the science is correct, though their clinical experience suggests the food order rules would be hard for a lot of people to stick to.
Both endocrinologist Rick Cutfield and registered nutritionist Nikki Hart say that to eat food in a strict set order is not what most people do. “I don’t know about you, but I like to have a little bit of this from my plate first and a bit of something else next,” says Cutfield, one of the country’s leading diabetes specialists.
Hart, who also works with diabetes sufferers, is blunter: "Nobody eats like this."
She says the system also relies on people having a fairly detailed knowledge of which food belongs in which of the three categories. It's not always obvious, when broad beans and quinoa, for example, are generous in both fibre and carbohydrate, and grapes are drastically more glycaemic than strawberries but also fibre-rich.
Although it doesn’t pass the test of practicality, the idea has potential, says Cutfield. He remembers a Māori patient attesting that he controlled his diabetes much more successfully by eating an apple cucumber before every meal than with any of the medicines he’d been prescribed.
"It improved his glucose levels, though, perhaps not surprisingly, was not taken up by other patients."
Hart applauds the veges-first ethos, saying adding vegetables to each meal has unarguable benefits: more valuable nutrients in the diet and a likely knock-on in appetite control.
However, both practitioners point out that by the time they see a patient, their eating habits have typically been entrenched for many years, so even the option of eating a bowl of salad first would be a hard sell. Behavioural change can be long and slow.
Hart says some of the trials on which Inchauspé's book is based were very small.
Cutfield says more evidence is needed. “The idea has theoretical promise, but would need testing in a real-world population including Māori, Pasifika and Asian patients with diabetes. Any food plan needs to be individualised, practical and affordable, and be a long-term option. The Mediterranean diet and plant-based diets have the best real-world evidence for healthy outcomes, in my opinion.”
Counting Calories
A further aspect of Glucose Revolution that may well push practitioners’ buttons is its enthusiasm for the growing evidence that the traditional “calories in, calories out” approach to dieting is reductive and simplistic. It’s now known that many factors, including muscle composition, hormonal cycles, digestion issues and tiredness, affect how many calories each person burns, even given identical food intake.
Inchauspé argues it's more important to consider that, at a molecular level, foods of an identical calorie count can nevertheless affect the body in vastly different ways. A San Francisco study that replaced overweight teens' carb consumption from fructose-rich foods (coated doughnuts, for example), to glucose foods (such as bagels), found their ailments and markers for disease – from fatty liver and high blood pressure to diabetes – all reversed in nine days. Several lost weight despite eating the same number of calories as before.
A University of Michigan study found a group who concentrated on flattening their glucose curve lost considerably more weight than a second group who concentrated on eating fewer calories – and the difference (7.7kg compared with 1.8kg) occurred even in cases where the glucose flatteners ate more calories than the calorie counters.
However, clinicians tend to value the calorie system as a reliable-enough guide for those trying to lose weight, and worry that anything likely to cause struggling dieters to second-guess it can lead to poor choices.
Inchauspé says she's had no pushback from the medical fraternity because her book is entirely evidence-based. She says new findings from randomised controlled trials tend to take a few years to percolate through to practitioners "because they're busy treating people".
She’s confident “veges first, carbs last” will become a new blueprint in time. She can cite dozens of positive outcomes from among her website subscribers. Two wrote personal testimonials for Britain’s Telegraph earlier this year, saying they’d lost more than 6kg each quite quickly by making what they regarded as no-fuss eating-order changes.
Fad gadgets & superfoods
Wearable health-measuring appliances such as glucose monitors may be the way of the future, but in New Zealand, apart from fitness devices and “smart” scales, such technology remains the preserve of the worried wealthy.
Glucose monitors are expensive and are currently not funded despite being of significant value in detecting high and low blood sugar, says endocrinologist Rick Cutfield.
“They are predominantly used by insulin-requiring patients and are not really validated for a non-diabetic population.” Minor glucose changes can be overinterpreted and cause stress, he says.
However, the Economist recently hailed wearable health trackers as a pending boon to medical science and public health, enabling early detection of ominous symptoms and providing new data pools for treatment and prevention improvements. It reported that diabetes monitors in the US had been found to save up to US$5000 per patient in health costs – a useful saving considering the diabetes treatment budget in the US is equal to half of what the country spends on its public schools each year.
Further breakthrough technology is coming in specially formulated superfoods. This refers not to the latest fad foods – acai berries, kale, bone broth and the like – but to plants found to have specially high concentrations of disease-inhibiting substances.
One is a hybrid of a wild Sicilian broccoli species that contains up to five times the quantity of sugar-inhibiting glucoraphanin than the standard variety.
Broccoli is a leading source of the substance, which the body processes into sulforaphane, an agent that activates genes that work to prevent excess blood sugar being stashed away.
Scientists at Norfolk and Norwich University Hospital’s Quadram Institute have trialled the anti-diabetic effects of a powdered soup produced from the super-glucoraphaninised broccoli. The American Journal of Clinical Nutrition reports that in the year-long study, participants with elevated blood sugar who ate the soup once a week saw their blood glucose levels drop to a normal range.
Researchers assessed the soup as more convenient and palatable than a multiple dose of capsules.
Flattening the curve
When UK Prime Minister Boris Johnson colourfully vowed to “stomp on the sombrero” of Covid-spread numbers, he might just as well have been talking about glucose management.
Healthy blood sugar requires the same basic epidemiological strategies. Knowing there will be an upward curve in exposure – to contagion and to glucose – the priority is to flatten that arc as much as possible.
Avoiding carbs altogether can be done, but is neither practical nor palatable. So, as with Covid organisms, the ideal is to put prudent barriers in carbs’ way so they’re less likely to cause widespread harm.
Though such measurements are mystifying to non-medicos, lab tests will classify a person’s blood glucose level as healthy at less than 7.8 millimoles per litre two hours after eating. Tests of over 11.1mmol/l two hours after food put you in the diabetic range.
From there, however, the “news you can use” is that the technical measurement of a healthily flat sombrero is a glucose spike of less than 1.7mmol/l. In snack terms, a salad, some nuts, plain yogurt or humus-dipped vegetables will yield way below that limit.
A blameless-seeming rice cake, however, can produce 3mmol/l; likewise an unarguably nutritious pear or a small handful of grapes.
This is where the “blocked sink” approach in Jessie Inchauspé's Glucose Revolution may help. A piece of whole-wheat toast might spike slightly above 1.7mmol/l, but add a modest topping of (unsweetened) nut spread and it stays comfortably below that level. Have a small handful of nuts with the pear or grapes and the curve is substantially flattened.
- Exercise: Studies have found moderate exercise taken after a meal – a stroll or some gardening or vacuuming – can considerably counteract glucose spikes.
- Vinegar: Yet another nouveaux-trendy fermented plant food, vinegar, in particular apple cider vinegar, has a suppressant effect on glucose. Cider vinegar has long waxed and waned as the diet-craze firmament’s miracle. But the glucose monitors appear unanimous: vinegar taken before or with a meal helps stomp down the sombrero.
- Adding fat, fibre or protein to carbohydrates: Glucose absorption will be slower if, for example, the apple crumble has cream on it, the biscuit contains nuts or the pasta has a rich sauce.
This, however, is the sort of information registered nutritionist Nikki Hart worries people will dwell unhelpfully on.
“It’s important that people don’t get tempted into additional high-fat and high-calorie food, because that’s going to undermine what they’re trying to achieve.”
Inchauspé says it’s simply useful to be aware that “clothing your carbs” will help neutralise their effect on blood sugar.
It’s important to keep the science in everyday perspective, she says. “If you’re going to eat a salad at every meal, [but] then eat chocolate bars and that sort of thing, it’s not going to do you much good.
“What the science tells us, though, is if you’re going to have a treat, this is how to reduce its harmful impacts.”
Glucose Revolution: the life-changing power of balancing your blood sugar, by Jessie Inchauspé (Penguin Life, $40)
This story was first published in the June 11, 2022 issue of the Listener.
