The emergence of smoothies as a health-conscious person’s choice of a snack (or even a meal) has been a great worry to me. These days no household is without a blender to make a delicious 'healthy' smoothie, and no lunchtime restaurant chain is without a vast selection to choose from.
But are smoothies really all that healthy? Let's take a look.
First, remember that fruit contains high levels of both glucose and fructose (sugars). When eaten in large amounts on regular basis, fruit will send your blood sugar levels through the roof. Make no mistake - fruit IS good for you when eaten in moderation and in its raw, un-processed, and - above all - fibrous form. Anyone with diabetes or any of the symptoms of metabolic syndrome or heart disease should only eat small amounts of fruit - perhaps two to three portions a day.
And herein lies the problem with smoothies - they contain large amounts of fruit, far more than you might think, and almost certainly more than you would normally eat. And that means a lot of sugar. For instance it was reported last year that one of Innocent's smoothies had as much sugar in a 250ml serving as you'd find in a 300ml can of Coke!
One patient in our clinic recently reported regularly drinking a 'Black and Blue' (dark berry) smoothie frequently, having been convinced that this was a healthy option. We found this particular drink to have 435cals and 95g of carbohydrate (in the form of glucose and fructose).
Let's say you have start your day with one of these smoothies (95g carbohydrate) and a few slices of thick-cut toasted wholemeal bread with jam (60g). You're hungry mid-morning and so you have a 'healthy' wholegrain snack bar and an apple (50g). At lunch you have another smoothie (95g) with a sandwich (50g in the bread alone, not counting any dressing / pickle). You have a small portion of potatoes with the evening meal (15gs) and fruit for pudding - let's say two thick slices of fresh pineapple (45g).
You have hit 410g of carbohydrate for the day, nearly half of which came from just two drinks. Most sedentary office workers will never burn that much sugar off. Insulin from the over-worked pancreas transports it from the blood to the muscles. When those have had their fill, excess sugars are converted to fat.
Your blood sugar levels are taking an absolute thumping, with sharp peaks at breakfast and lunch. You're likely to feel hungry mid-morning and then again mid-afternoon, so the temptation will be to get a snack. And, the more sugar you consume, the more insulim your body has to make, and you run the risk of becoming insulin resistant. Not only that, all this excess carbohydrate drives up your Very Low Density Lipoproteins (VLDLs) which oxidise in the arterial wall and cause atherosclerosis, a narrowing of the arteries. This is perfect conditions for a clot to appear and cause a heart attack.
Well, here's the really scary part: this actually happened to a gentlemen I know. He had a heart attack late April and then came to us afterwards. We carried out a retrospective assessment of his diet (which he had thought was excellent) and found it remarkably similar to that described above.
We made some changes, so that the carbohydrate content in his diet dropped to below 75g per day on average. Within two weeks he had lost 2kg, with 7kg more to lose. Just a few days ago he told us "I am fantastic, I can’t believe how good I feel." It makes us feel good too.
Through experience I have found that if someone can keep the carb content to between 75-100g per day they should experience effortless fat loss as long as other lifestyle and exercise factors fall into place.
The power of simple diet, exercise and lifestyle changes never ceases to amaze me - but 'conventional wisdom' in the form of confusing health messages make it difficult for people to know what to do. They know they can't lose weight (and they are risking so much more than being overweight) but they just don't know WHY.
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