The “Newcastle Diet,” as it seemingly is practiced today, is not the same as the original diet developed at Newcastle University for their “Counterpoint Study,” conducted in 2009 and published in 2011. I wrote about this study four years ago in "Reversal of Type 2 Diabetes" (#88) and "'Reversal of Type 2 Diabetes' Revisited" (#89). Column #88 garnered the most page views of any column I have ever published due to the appealing but misleading title. Note: My column titles were in quotes because they are the paper’s authors,’ not mine.
The author’s use of “reversal” in the title is misleading because of their definition of “reversal”: “Reversal of diabetes” was defined by them as “achieving fasting capillary blood glucose < 6.1mmol/l [110mg/dl] and/or, if available, HbA1c less than 43 mmol/mol (6.1%) off treatment.” In my book, that is neither a “reversal” nor a “cure,” as some would claim. A FBG of 110 is smack in the middle of “pre-diabetic” (which begins at 100mg/dl (5.6mmol/L) in the U.S). By way of reference, many doctors consider an A1c of 5.7% (39 mmol/mol) – the threshold for “pre-diabetes” – to be incipient type 2 diabetes. That’s because it’s manifest evidence of Insulin Resistance (IR), the cause of type 2 diabetes. “Pre-diabetes” is simply an arbitrary point on the IR continuum.
Why is the Newcastle Diet called the “600 kcal diet”? Quoting from the Newcastle University 2011 paper, the dietary protocol of the “Counterpoint Study,” “consisted of a liquid diet formula (46.4% carbohydrate, 32.5% protein and 20.1% fat; vitamins, minerals and trace elements; 2.1 MJ/day [510 kcal/day]; Optifast; Nestlé Nutrition, Croydon, UK). This was supplemented with three portions of non-starchy vegetables such that total energy intake was about 2.5 MJ (600 kcal)/day.” That’s why the Newcastle Diet is called the “600 calorie diet.”
However, Diabetes.co.uk, which funded the study and has the only official description of it on the web, now says it is 800 kcal diet, comprised of “Optifast meal replacement sachets, which provided 75% of the calories (600 calories). The other 200 calories came from non-starchy vegetables.” Then, “Note: The diet is referred to as the 600 calorie diet (rather than 800) due to the meal replacement aspect of the diet totaling 600 calories.” Wrong! The Optifast portion is 510 kcal, but I guess NHS doesn’t want Brits trying such a “drastic” (600k cal total) diet, and certainly not “without the help and approval of a dietitian or doctor.” Good luck with that!
Note also the macronutrient composition of the Optifast part of the original Newcastle Diet: 46.4% carbs, 32.5% protein, and 20.1% fat. That’s high carb, very high protein and low fat. And that’s not counting the 3 servings of “non-starchy vegetables,” which if you ate them would boost the carb content higher, to 55% of the 600 kcal diet and 66% carbs in the 800 kcal diet. That is how you developed diabetes in the first place!
In addition, the 32.5% protein is much too high. Virtually no one recommends more than 30%, and hardly anyone eats more than 20%. Americans eat 15% on average, and the Nutrition Facts panel on packaged and processed foods is based on 10% protein. Any protein that your body does not take up in 4 or 5 hours is stored in the liver and is used to make glucose (or fat!). In T2s, suppressing this unwanted gluconeogenesis is one of the things that Metformin does. So, basically, Newcastle is a low-dietary-fat diet, but since your body has access to its own fat for fuel, if you burn a pound a week, it’s a pretty HIGH-FAT diet AT THE CELLULAR LEVEL.
Okay, so why does this diet work? The answer is that it is fundamentally a very low CALORIE diet. On this the authors agree. They conclude, “Normalization of both beta cell function and hepatic insulin sensitivity in type 2 diabetes was achieved by dietary energy restriction alone” (my emphasis). Makes sense. You eat less. You lose weight. In this respect the Newcastle diet is similar, both in mode and outcomes, to bariatric surgery…but tremendously safer. And in lieu of the 300g of carbohydrates that the typical Western 2,000 kcal diet includes, the original Counterpoint Study (600 kcal) version would have 59g of carbs from Optifast and 23.5g added for “non-starchy vegetables” = 82.5g total. So, in addition to being very low in DIETARY fat, the original Newcastle is low carb! In the higher-fiber 800 kcal version recommended by Diabetes.co.uk, the carb count climbs to 132 grams, no longer considered “low-carb,” but it’s still pretty low compared to 300 or 375! Good for the gut too.300g of carbs is the RDA in a 2,000kcal diet; 375g in 2,500kcal (for men). Surely everyone knows, even if the NHS and the ADA and the public health establishment won’t admit it, TYPE 2 DIABETES IS A DIETARY DISEASE. As such, the best treatment for type 2 diabetes is a HIGH fat, moderate protein, LOW carbohydrate diet.