Saturday, May 28, 2011

Study: Metabolic and Behavioral Effects of a Low Fat, High Sugar Weight Loss Diet

What would happen if you put 42 overweight women on a diet supplying only 11 percent of energy as fat and 71 percent as carbohydrate, with half of those women getting 43 percent of their total daily energy (kcalorie) diet from sucrose, plain white table sugar?

I don't recommend eating a 43% sucrose diet, but I do have interest in knowing how sugar affects human metabolism and behavior, as I think that this could help us understand the baseline adaptation of human metabolism.

Surwit et al did the experiment.  The women weighed 130 to 200 percent of their ideal bodyweights at baseline.  Surwit et al controlled dietary intake by providing the women with all meals and snacks consumed during the 6 week period, along with a Women's One-A-Day multivitamin.

Half of the women ate a starch-based diet and the other half ate the high sucrose diet.  Each of the groups included 12 "whites."  The high sucrose group had 8 "blacks," and the high starch group had 10.

This table shows the nutrient profile of the two diets; one supplied 121 g of sucrose daily, the other only 12 g sucrose daily:

You can see that without the multivitamin contribution, the high sucrose diet has a low nutrient density compared to the high starch diet.  Of concern to me, with the multivitamin added, both groups had quite high intakes of iron.  High levels of dietary and stored iron appear to promote multiple degenerative, inflammatory, and autoimmune disease processes, as well as aging, by enhancing oxidative activity throughout the body.   Since these diets supplied essentially adequate dietary iron without the supplement, no one who did not have iron-deficiency anemia needed this amount of additional iron and I would have had them take an iron-free supplement in this study.  Outside this study, I would have taught them to make natural food selections to optimize iron intake.

And this table shows a sample day's menu for each of the groups.

Lots of refined foods...not what I would suggest.  Lots of room for improvement.

The following figure depicts the changes in body weight during the intervention:

Surprise!  Both groups lost weight.  According to this table, the loss included trunk fat and a decline in body fat percentage:

 The loss of trunk fat suggests a decline in insulin resistance, since trunk fat is a sign of insulin resistance or metabolic syndrome.

Total cholesterol, LDL, and triglycerides also declined, with minimal reduction in HDL:

Both groups had reductions in fasting glucose and marked reductions in levels of norepinephrine, a "fight or flight" neurotransmitter (declining levels of which would indicate reduction of perceived stress and tension):

The authors noted:

"Interestingly, one 53-yold subject who displayed the typical pattern of markedly elevated plasma triacylglycerol and hyperglycemia at the beginning of the study showed significant decreases in fasting glucose, total cholesterol, LDL-cholesterol, and triacylglycerol concentrations, and an increase in HDL cholesterol during the 6 wk of the high-sucrose diet. These findings are consistent with epidemiologic data (1, 9, 22, 39) and animal data from our laboratory (13) that clearly show that high sucrose or complex carbohydrate consumption does not cause obesity, hyperglycemia, or insulin resistance in the absence of dietary fat."

Wait...with all that carbohydrate and so little fat and animal protein, didn't they feel hungry all the time?  The following table shows the "behavioral"--actually, psychical, or mental-emotional-- effects of these diets:

Hunger, negative feelings, and depression all declined from baseline in both groups; vigilance and positive feelings both increased from baseline in both groups.  Anxiety declined in the starch-based group, and slightly increased, but not significantly, in a statistical sense, in the sugar-based group.

The authors noted in the introduction:
"Although there is little theoretical rationale to support the notion that sucrose produces behavioral arousal, there are data to support a theory making the opposite prediction. Carbohydrate consumption, in conjunction with a minimal amount of protein, has been shown to cause an increase in the ratio of plasma tryptophan to large neutral amino acids (28), which in turn is associated with an increase in central tryptophan uptake and brain serotonin synthesis (29, 30). Furthermore, sucrose has a greater effect than starch. (28). This carbohydrate-induced change in central serotonin activity would presumably have a tranquilizing effect as opposed to the exaggerated arousal and hyperactivity typically attributed to sucrose (31). "
Combined with this information, this study's findings that high sugar intakes can markedly reduce norepinephrine and hunger levels confirms the Chinese medical view that sugar has yin effects, where yin stands for the overlapping sensory characteristics cool, calm/quiet, soft, and moist.  According to Chinese medicine, this makes sugar a medication for excessive yang conditions characterized by heat, agitation, tension, and dryness; but because it has relatively extreme characteristics, long term regular use of large amounts will create an excessively yin condition, i.e. excessive coolness, lassitude, weakness/impotence, and moisture (e.g. watery phlegm accumulation, excessive salivation), and a generally deficient condition.  Chinese dietary principles classify whole food starches as more desirable, more balanced foods--having a balance of yin and yang characteristics making them suitable for use as staple foods.  More on that in another article.

Meanwhile, this study seems to question claims that diets high in sugar or starch and low in fat will increase hunger, raise blood sugar, increase lipids, and promote metabolic syndrome in obese individuals.  On the contrary, in this study, increasing the carbohydrate content of the diet, whether by starch or sugar, had the opposite effect.

It seems very unlikely that this would occur in any animal with a metabolism by nature designed for a low carbohydrate and high fat intake.  I would expect high-carbohydrate, low-fat diet to increase, not decrease, stress and tension in an animal evolutionarily adapted to a low-carbohydrate, high-fat diet.

On the other hand, it suggests a dietary remedy to replace the most commonly prescribed drugs in the U.S.A. -- antianxiety and antidepressant medications.

Can you reverse depression, negative feelings, poor vigilance, and hunger all with one simple dietary shift to increased whole food starch and concomitant reduced fat?

A comprehensive theory of human nutrition and weight management has to have the capacity to explain this study without trying to explain it away.


Organism as a Whole said...
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Organism as a Whole said...
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Organism as a Whole said...

Sucrose has different effects on male and female rats. Perhaps that applies to humans too.

For instance,

Female Rats are Protected against the Pro-Oxidant Effects of a High Sucrose Diet

Female Rats Do Not Exhibit Free Fatty Acid–Induced Insulin Resistance.

There was a similar study done on women. It was a 15-day trial on a high-fat, high-starch, and high-sucrose diet. There were the same results; women who lost the most weight were in the sucrose group.

There was also a slight increase of adrenaline in the sucrose group.

I am skeptical of those studies, because they didn't mention the specific foods in which the fat, starch, or sucrose groups ate. The sucrose group have well just ate healthier foods than the starch group.

The starch group may have foods which were more processed, such as alloxan-tainted white bread enriched with iron or unprepared whole grains with added vegetable oils. While the sucrose group may have foods which were relatively unprocessed like orange juice.

Also, as I noted above, men might differ from women.

It doesn't prove that sucrose, in itself, is superior to fat or starch, as it may simply be that processed foods were preventing weight loss.

Those studies, as you may know, just demonstrate that sucrose isn't very harmful for women. I think that was your main point.

SamAbroad said...

Is there any study examining a weight loss diet that didn't have beneficial outcomes for health? I've never come across one.

Restricting calories will bring about decreases in hunger, for a time.

That's the main problem with nutritional science. Most trials are too short-term to derive any meaningful conclusions.

Joe said...

SamAbroad's point is a good one, the study was too short to show any lasting effect.

The test participants were overweight at the start, if they lost weight in six weeks, their bodies were cannibalizing their own fat stores. So they may have been eating low fat, but their metabolisms were running high fat.

It seems the goal of this study was to exonerate sucrose. Fine, but the glucose load of both diets was huge. Based on what they were fed, I would bet the blood sugar numbers of the low-sucrose group were worse than those eating table sugar.

Stan (Heretic) said...

Facts are right but conclusions are incorrect!

The dieters were not on a low fat diet, they were on a high fat medium carbohydrate, low caloric diet!

They consumed only about 1000kcal/day out of carbohydrates.

The were drawing the rest of the energy, which may have been close to another 1000kcal (on top of those from the diet carbs) - out of their own body fat. They were "consuming" their won body fat!

For a comparison, a high caloric Western diet with ~3000kcal/day and 60% carbohydrate would provide 1800kcal/day of carbs!

No wonder the study participant's insulin secretion would have been probably close to one-half of their previous baseline condition. Therefore, their leptin secretion would have been correspondingly higher!

Lower insulin = higher leptin!

High leptin = "consuming" own body fat = weight loss!

Stan (Heretic)

Don said...


The high fat theory is that eating carbs stimulates insulin and makes you hungry and stops the release of fat from storage, preventing fat loss; therefore, to lose weight you have to eat low carb, high fat diet.

This study found that its not necessary to eat a low carb, high fat diet to reduce insulin, control hunger, or lose body fat.

Burning body fat is not the same as eating dietary fat.

Although I made this same mistake myself not too long ago, I now find it a little humorous to find people telling me that you have to eat a low carb diet to lose fat, because eating carbs will prevent fat loss, but then try to call a high carb diet "high fat" because it involves using body fat. If you really believe that a high carb low calorie diet is metabolically the same as a low carb high fat diet, why argue about for the latter and denigrate the former?


These people were consuming 250 g of carbohydrate daily. A low carb diet would have <100 g daily. They ate at least double the carbohdyrate recommended by most advocates of low carb diets. Now you turn around and call it a high fat, low carb diet.

I used to think like you, but now I consider it a sleight of words to say that they were on a high fat "diet." Diet refers to what we eat, take in from the external world, not what we burn from our own stores.

And, where did that body fat come from originally? As I will show in future posts, we can be sure that most of it came from dietary fat and protein, not dietary carbohydrate. Very careful studies have repeatedly confirmed this.

Organism as a whole,

I didn't bring this out to suggest that sucrose isn't harmful to women (it is). I simply wanted to show that some studies show that people can lose weight, feel good, and have reductions in hunger on high carbohydrate diets, even if refined carbs, all contradictions to the idea that high carb diets make people hungry, cranky, and impede weight loss.

It also contradicts the claim that fructose causes insulin resistance, since these people ate ~60 g of fructose daily while showing an improvement in metabolic syndrome markers.

tradingkellys said...

Like others have said, these people were on an 1,100-cal-per-day (i.e. starvation) diet. If Don wants to give the paleo / primal / low-carb / whatever world something to chew on, show us a study where the participants are eating in order to maintain their weight, but eating drastically different macronutrients.

If I'm not mistaken, paleo-ish clinical trials have already done exactly that and found lower carb to be better for every marker.

Also, if I'm reading this chart correctly, the percentage of body fat lost after this 6-wk starvation diet were negligible. (1% to 1.5%?!?)

Don is going Matt Stone & Ray Peat. That's fine: Everyone needs a niche and the "Paleo + High Carb" world is sorely unpopulated at the moment and could use a few more players who act as contrarians to the echo-chamber. It's a valuable service, and allows those of us who care deeply about the science to re-think and re-examine our views--even if not to change them.

Anyone who has looked at the data understands that people can function very well on non-toxic, very-high-carb diets and that the human body is built to handle glucose. At this point, it's just knocking down a straw man to point that out. The question is whether the modern food supply and lifestyle has wrecked an individual's metabolism, hormonal signaling, etc. that a carb-heavy diet cannot work.

Don said...


I don't know of a paleo diet study lasting more than 12 weeks, and one of them certainly had plenty of carbs from carrot juice, honey, and fruit, yet showed numerous metabolic improvements compared to a Mediterranean diet.

Plenty of high carb, low fat, maintenance calorie and surplus calorie studies have been done. As I discuss them you will be surprised, I think, to see the results. The don't at all support the carbs make you fat and destroy your metabolism belief. Some of these have also been done with "damaged" metabolisms, i.e. diabetics.

Can a person stay lean on a high carb, low fat diet, maintenance diet, without counting calories, for a whole lifetime? Clarence Bass.

"If you eat the right things you can almost eat as much as you want and still lose fat; it's actually hard to overeat. What happens is you become full and satisfied before you take in more calories than you burn.

The details are in my books. But here's a brief summary: my eating style is low in fat (ample good fat), high in unrefined carbohydrates (whole foods) and near vegetarian (skim milk, a few eggs, and fish). There's plenty of good quality protein for the hardest training athlete. All the macro- and micro-nutrients are there. It's healthy, balanced - and satisfying.

Finally, I almost never count calories. You won't have to either, once you master the "Ripped" style of eating."

For those of you that keep making the ethnic group argument (i.e. Asians stay lean on low fat diets but Caucasians get fat), notice that Clarence is not African, nor Asian.

Don said...

BTW, I don't see any similarity between my approach and Matt Stone's or Ray Peat's, except that it just doesn't fit with so-called "paleo" dogma. I'm not speculating about body temperature, thyroid, or making outlandish claims about "high everything" (you can't have "high everything") or "there are no essential fatty acids."

Ed said...

Stephan Guyenet I think might explain the results via food reward and bodyfat setpoint. I tend to agree with the idea that the only way to lose body fat without hunger is if the setpoint drops. The broad idea at work is that a monotonous, bland diet drops the setpoint. That could be a high starch or even high sugar diet, so long as it's bland and/or monotonous.

Don said...

Oh, about the 1-1.5% body fat % loss.

The high sucrose group went from 97 kg down to 89 kg, lost a total of 8 kg in 6 weeks, 17.6 pounds, so almost 3 pounds per week. Not negligible.

The starch group went from 96 kg to 89 kg, lost a total of 7 kg, 15.4 pounds, 2.6 pounds per week. Not negligible.

Percentage body fat dropped 1% in the high sucrose and 1.5% in the high sucrose. The high sucrose group was 50% fat (obese) and 97 kg at start, hence, 48.5 kg body fat. At end of 6 weeks, high sucrose group was 89 kg, 49% fat, hence 43.61 kg fat. So they lost average of 4.89 kg fat, i.e. 11 pounds of fat, almost 2 pounds of fat lost per week...again, not negligible. Sustained, they would lose 95 pounds of fat in a year, about the max anyone can expect. Numbers are similar for the high starch group.

Oh, and about the 1100 kcal intake. Supposedly "starving." Why then did they report a reduction in hunger? How about the idea that eating most of their calories as carbs made it possible for them to stay at 1100 kcal?

If people on a low carb diet report low hunger on low calories, its because the diet wards off hunger.

But if a people on a high carb diet report low hunger on low calories, its because "its just a short term study" or "any low calorie diet will curb hunger for awhile."

Most low carb studies are also short term. And if low calorie explains loss of hunger on low fat high carb, then it can equally be the explanation for loss of hunger on low carb high fat. If indeed it happens.

tradingkellys said...

I look forward to any and all studies that you discuss. I just don't find ones that involve severe caloric restriction to be compelling on the macro-nutrient question. ["Starvation" doesn't imply hunger; anyone on a long fast is starving, but often report euphoria and being hunger-free. The calories these subjects were consuming v. what they weighed means they were vastly below maintenance. I'm thrilled they were happy and satiated. If I snorted cocaine for 6-wks straight I would be too, but I won't write a blog entry to promote it.]

From where I sit, the total-weight v. fat-loss numbers undermine this entire diet. First, losing 2 lbs a week when you are 20-35% body fat might be fine when severely deficit-ed. But when you're almost 50% body fat, 2 lbs is nothing. (To your Clarence Bass, n=1 example, I give you the Biggest Loser, where the similarly obese contestants drop 10 lbs a week for the first 6 weeks.)

Second, your calculations reveal that at best two-thirds of the weight loss in the subjects was fat. Again, when you are 50% fat, it's incredibly unnerving that you are losing 33% non-fat in your high-sugar diet. It's not surprising in the least, given the macro-nutrient ratios consumed, that the subjects lost 5 pounds of muscle and organ tissue. (But wait! It was really high fat! ....)

BTW: My dietary advice to anyone who asks is to eat non-toxic, nutrient-dense foods. (Maybe we'd disagree on what's in that list.) I think macro-nutrient ratios are 100% individualized and best discovered through lots of self-experimentation.

It just so happens that a large (and vocal) group of people succeed wildly on AHA-bucking high-fat, low-carb diets---and that those people go back to storing fat when they get back on carbs. Maybe ketosis wrecked their metabolisms! But, more likely, their bodies just work better that way. [And, I should point out, a similarly large group succeeds on AHA-following low-fat diets. Okay. Maybe it's all about food reward and palatability, as Stephan has been discussing.]

Stan (Heretic) said...

Don wrote: - "Oh, and about the 1100 kcal intake. Supposedly "starving." Why then did they report a reduction in hunger?"

Because their insulin level dropped; simultaneously their leptin level must have gone up allowing them to utilize ("consume") their own body fat!

- "How about the idea that eating most of their calories as carbs made it possible for them to stay at 1100 kcal?"

Has nothing to do with what they ate, as long as they ate less carbohydrate than before! Do the math: probably around 1500kcal of carbs or more before the diet (I assume here, for the sake of discussion, an average 2500kcal/d and 60% carbs), and 1000kcal out of carb while on the diet!

- "If people on a low carb diet report low hunger on low calories, its because the diet wards off hunger."

Report lower hunger only in the first period while their own body fat reserves are full enough, and only for those people whose leptin secretion and leptin action is not impaired. This study, i.e. weight loss using 1000kcal of dietary carbs, would not have worked for everyone, you probably known this. Ask people who tried Weight Watchers' once - WW almost always works the first time around. Then ask people who tried Weight Watchers several times. There is a clear pattern in this. Leptin hormone seems to stops working the same way after several weight loss "yoyo" dietary cycles like that.

- ''But if a people on a high carb diet report low hunger on low calories, its because "its just a short term study" or "any low calorie diet will curb hunger for awhile.''

Yes. Typically for up to a few months while they can "consume" and can "supplement" their meagre diet out of own body fat. After wards they hit a "wall" and snap out of it. Regain all weight plus some, then may repeat a "healthy" veggie diet and so on. Have seen that countless of times (on other people).

Another "brick wall", much more serious they encounter after about 5-10 years if they persist on a strict vegetarian diet. Serious malnutrition sets in and their health typically deteriorates rapidly. Again, seen that many times reported on various vegetarian discussion groups, some really fascinating from a medical point of view.

- "Most low carb studies are also short term."

Yes but personal experiences of people on such HF diets as Kwasniewski's "Optimal Diet" are much longer than that. Some date from around 1980-ties.

For example, I have been practicing a high animal fat low carb nuttrition principles myself continuously since July 1999. It is like a "paleo" but more animal fat, dairy fat and eggs, and less meat.

- "And if low calorie explains loss of hunger on low fat high carb, then it can equally be the explanation for loss of hunger on low carb high fat. If indeed it happens."

Yes of course it does happen, but it is more complicated that that. That is we do not have to live of our own body fat yet our caloric intake is still about 30% lower than other people (based on Kwansiewski's published data).

For example, my body weight is stable at 67kg, 173cm and my average caloric intake is ~1500kcal (1300-1700), 70% of it is out of animal fat, about 50g of carbs, per day. I am 55. It has been like that since 1999. This is considerably less than an average expected for my body size on the usual high carb diet. It would have been expected to be about 2400kcal.

Am I hungry? Never! Am I burning off my own body fat like those high carb low cal dieters? Of course not! Not for those 12 years at least.

I have no explanation on why my caloric intake is so low yet sufficient to sustain my active energetic life style (such as working on two jobs), other then perhaps by the theory of higher metabolic efficiency of a high fat nutrition versus a high carb one.


Stan (Heretic) said...

Don wrote: - "It also contradicts the claim that fructose causes insulin resistance, since these people ate ~60 g of fructose daily while showing an improvement in metabolic syndrome markers."

No it doesn't contradict that. They consumed significantly less carbohydrates including fructose than before, thus all their markers had improved.

- "These people were consuming 250 g of carbohydrate daily. A low carb diet would have been [less than] 100 g daily."

Doesn't matter, it does not have to be 50g, just the lower the better! 100g is healthier than 250g and 50g wold have been healthier than 100g. I called that "high fat medium carb" because that is what it was, metabolically.

STG said...

It would be an interesting debate if you could have a podcast with Gary Taubes and/or Dr. Robert Lustig to discuss this study.

izigr said...

I second STG's comment, but maybe with a "carb agnostic" like Robb Wolf or Richard Nikoley in there as well.

Anonymous said...

Peter of Hyperlipid has a commentary on the Surwit study.