“The thirty-year-long campaign against dietary fat is as misguided as it is futile”.
That statement, written in The New Diet Revolution by Dr. Robert Atkins, is now being vindicated with startling regularity as new research continues to show. There’s good reason to believe that even mainstream researchers have come to realize that the demonization of all fat- including saturated fat, as we will see in a moment- was ill-advised and misleading. This is a good time to clarify the position of the Atkins Nutritional Approach on fat in the diet, particularly the most misunderstood of all fats, saturates.
All foods containing fat- even pure oils- contain a mixture of three kinds of fat- saturated, polyunsaturated and monounsaturated. (Foods are often identified by their predominant fat- for example, olive oil as “monounsaturated” butter as “saturated” – but all real foods contain mixtures of the three).
It is the position of the Atkins Nutritional Approach that all three types of fats are necessary and important to human health and should be incorporated into the diet in a balanced proportion. It is also the position of the Atkins Nutritional Approach that saturated fat, particularly in the absence of high carbohydrate intake, is not dangerous to human health—on the contrary, when balanced with mono and poly-unsaturated fats in a controlled carbohydrate dietary environment, saturated fat may actually have real and measurable benefits in a number of different arenas. More on that in a moment.
The very first edition of Diet Revolution in 1972, in its zeal to get the word out that sugar, processed carbs and unfettered insulin responses were responsible for the growing epidemics of obesity and heart disease, Dr. Atkins did in fact mention in passing that it was probably better to eat pork rinds than to fill up on sugary cakes. Because of this, taken out of context and blown out of proportion, there continues to be an enormous amount of prejudice against the Atkins Nutritional Approach as the “diet that promotes unlimited amounts of saturated fat”. This wasn’t true then, and certainly isn’t true now. Meticulous analysis of the daily food menus for the three phases of the Atkins Nutritional Approach reveals a very balanced intake of fats.
In the Induction Period, for example, amount of total fat consumed averaged over a seven day period comes out to 126 grams, of which the majority is monounsaturated: 55 grams to be exact. The remaining fat consists of 37grams of saturated and 21 grams of polyunsaturated. As a percentage of total fat consumed this comes out to a little less than 1/3 (30%) saturated, about 2/5 (40%) monounsaturated, and about 1/5 (22%) polyunsaturated. Note that even conservative government recommendations say that 1/3 of fat consumed can be from saturated fat!
In Ongoing Weight Loss, the percentage of total fat from saturated fat is even less. A typical one day menu on the OWL stage has about 118 grams of total fat of which only 33 grams are saturated, making saturated fat intake 16.7% of total calories consumed for the day and considerably less than 1/3 of the total fat consumed.
Now here’s where it gets good: Let’s say the average overweight American is, for example, consuming 3500 calories a day- a figure that’s probably an underestimation considering that one triple cheeseburger from Wendy’s weighs in at 940 calories and a Frosty drink to wash it down with is 540. Now let’s further say that our typical American is sticking conscientiously to the “official guidelines” of 30% of calories from fat, 10% from saturated. That typical American would be in fact consuming on a daily basis 116 fat grams of which 38 grams would be from saturated: that’s virtually the same amount as the induction stage of the ANA, and actually 5 grams more than the OWL stage! And, needless to say, neither of the Atkins stages would also contain the gut-busting, obesity producing sugar and carbs that our average American would be eating along with his fat on a daily basis.
But is saturated fat really the demon it has been made out to be? Even some “low-carb” diet book authors buy into this myth, designing so-called “healthy” versions of controlled carb programs that cut the contribution of saturated fat even further. Is this necessary? What does the research say?
Hays et al (1) followed the medical records of 151 patients who had been prescribed a diet of high saturated fat, but were not allowed any starch whatsoever. He compared these patients to a similar group which ate a diet that contained low saturated fat but moderate amount of starch. (Both groups consumed high monounsaturated fat). Here’s what he found: The high saturated fat/ no starch group had greater reductions in hemoglobin A1c (a diabetes marker). The high saturated fat/ no starch group had additional weight loss. And the high saturated fat/ no starch group had additional decreases in cholesterol! The conclusion of the researchers: “Addition of saturated fat and removal of starch from a high monounsaturated fat and starch restricted diet improved glycemic control and were associated with weight loss without detectable adverse effects on serum lipids.” (1)
Hays (2) and colleagues did another study on the effect of a high saturated fat / no-starch diet, this time measuring the effect of the diet on type of LDL cholesterol. We now know that LDL (known as the “bad”) cholesterol comes in two “flavors” or, more accurately, “particle sizes”. One of these is particle size pattern A, which are large fluffy molecules which are actually pretty benign. The other is particle size pattern B which is like a small dense BB-gun pellet. This pattern is the dangerous type of LDL cholesterol, most likely to lead to plaque and most predictive of heart disease. Recent research has focused on the changes in particle size in LDL cholesterol as a response to different diets- this measure is much more sensitive and telling than just the absolute number LDL cholesterol. In the Hays study, all subjects had atherosclerotic Cardiovascular Disease, and all were obese. They were told to consume one half of all calories as saturated fat (primarily red meat and cheese). Fruit and non-starchy vegetables were prescribed in restricted amounts at each meal, but starch was completely forbidden. Both body weight and body fat percentage decreased in the study group, as did triglycerides. But here’s the really key part: though total HDL and LDL did not change, the size of the particles did! With a diet of fully 50% of calories from saturated fat, the patients saw their risk profile change significantly for the better. In fact, 10 of the 23 patients had a profile that indicated metabolic syndrome at the beginning of the study, even though they had been treated with statins. But by the end of the study, and after consuming a diet that averaged 1- 1 ½ pounds of red meat and 2-4 eggs per day, 8 of the 10 metabolic syndrome patients had changed to a low-risk profile!
Many, many other studies have been done in the past several years using the protocol of the Induction Phase of the Atkins Nutritional Approach and we now have a fair amount of hard data to demonstrate that consuming approximately 30% of total fat intake from saturated fat on a low-carbohydrate regimen does not constitute a health hazard at all and may in fact have a number of benefits (for example, the positive change in LDL particle size discussed above). Volek, et al, (3) conducted a study which compared the results of a low-fat diet to a low-carb diet. The low-carb group consumed about 60% of their total calories from fat, and of this, about 1/3 was saturated. While these subjects experienced a mild increase in total and LDL cholesterol, their HDL (good, protective) cholesterol increased twice the amount that their “bad” cholesterol did, resulting in a significantly improved cholesterol risk profile. The subjects also experienced a large drop in triglycerides, leading to a superb Triglyceride: HDL ratio, a measure which has been shown in at least two studies (Jeppesen, et al Circulation 97:1029, 1998, and Gaziano, JM et al Circulation 96(8):2520-2525, 1997) to be a significant marker and predictor for cardiovascular disease.
Other studies have examined the results of a typical Atkins induction diet (usually about 50-60% fat with 1/3 of it coming from saturated). Sharman, Kraemer, et al (4) found that Total cholesterol, LDL cholesterol and oxidized LDL cholesterol were unchanged but HDL tended to increase. Triglycerides dropped significantly and in subjects who had previously had a predominance of those small LDL particles (pattern “B”) there was significant change for the better in LDL particle size. Vernon, Mavropoulos, et al (5) found that type ll diabetics using a classic Atkins diet beginning with the Induction phase and moving upwards in carb allowance at the usual rate of 5 grams per week reduced their hemoglobin A1c levels with half of them reaching fully normal (non-diabetic) readings by the end of the study. They also found their diabetic subjects had significant reductions in total cholesterol and serum triglycerides and were able to noticeably reduce their medication. Sondike, et al (6) put adolescents on an Atkins diet beginning with Induction and compared them to a matched group of teenagers on a standard low-fat diet. The Atkins dieters lost more weight and had no negative changes in their blood lipid profiles. Some innovative work by Dreon suggests offers further evidence that saturated fat in the diet may be responsible for a desirable increase in LDL particle size, a result not seen with low-fat or reduced-fat diets (7-10). And it’s worth noting that as far back as 1981 a study of native societies in Polynesia that ate well over 50% of their calories from saturated fat (coconuts) had vanishingly low levels of heart disease. (11)
The benefits of monounsaturated fats (like olive oil) are well known and well documented, and the benefits of specific polyunsaturated fats like the omega-3’s found in fish (Eicosapaentanoic Acid and Docasahexanoic Acid) are now beyond dispute. There is a tremendous amount of peer-reviewed literature documenting their positive effects on everything from heart health to depression. The position of Atkins Nutritional Approach has always been- and will continue to be- that the best possible eating plan contains a balance of the three types of fats in the context of a controlled carbohydrate diet of natural, unprocessed foods.
A balanced intake of all three categories of fats- monounsaturated, polyunsaturated and saturated, consistent with the ANA recommendations, will lead to both significant weight loss and to the improvement of cardiovascular health.
1. Hays Results of Use of Metformin and Replacement of Starch with Saturated Fats in Diets of Patients with Type ll Diabetes
2. Hays et al Effect of a High Saturated Fat and No-Starch Diet on Serum Lipid Subfraction sin Patients with Documented Atherosclerotic Cardiovascular Disease
3. Volek, Sharman, et al An Isoenergetic Very Low carbohydrate Diet Improves Serum HDL Cholesterol and Triacylglycerol Concentrations, the Total Cholesterol to HDL Cholesterol Ratio and Postprandial Lipemic Responses compared with a Low Fat Diet in Normal Weight, Normolipidemic Women
4. Sharman, Kraemer, et al A Ketogenic Diet Favorably Affects Serum Biomarkers for Cardiovascular Disease in Normal-Weight Men
5. Vernon, Mavropoulos, et al Clinical Experience of a Carbohydrate- Restricted Diet: Effect on Diabetes Mellitus
6. Sondike, et al Effects of a low-carbohydrate Diet on Weight Loss and Cardiovascular Risk Factors in Overweight Adolescents.
7. Dreon, DM et al Change in dietary saturated fat intake is correlated with change in mass of large low-density-lipoprotein particles in men Am J Clin Nutr 1998, 67(5): 828-36
8. Krauss RM and Dreon DM Low-density-lipoprotein subclasses and response to a low-fat diet in healthy men Am J Clin Nutr 1995, 62(2): 478S-487S
9. Dreon DM A very-low-fat diet is not associated with improved lipoprotein profiles in men with a predominance of large, low-density lipoproteins Am J Clin Nutr, Mar 1999; 69 (3): 411-418
10. Dreon DM et al Low-density lipoprotein subclass patterns and lipoprotein response to a reduced-fat diet in men FASEB J 1994;8:121-126
11. Prior IA et al Cholesterol, coconuts, and diet on Polynesian atolls Am J Clin Nutr 1981 Aug; 34 (8): 1552-61