Why I Don’t Worry About Sugar

Most of the peo­ple I talk to about nutri­tion are con­vinced that car­bo­hy­drates are their ene­my. They think that “sug­ar spikes” cause dia­betes. (They have it back­wards. Sug­ar spikes are the result, not the cause of dia­betes!) Peo­ple seem to be par­tic­u­lar­ly wor­ried about the effects of a sug­ar called fruc­tose. Per­son­al­ly, I’m not wor­ried about car­bo­hy­drates, even fruc­tose, as long as it’s found in an unre­fined plant source. I even think that adding a spoon­ful of sug­ar or per­haps some maple syrup every now and then could help a lot of peo­ple stick to a healthy low-fat, plant-based diet.

Genet­i­cal­ly, human beings are almost iden­ti­cal to chim­panzees. Our DNA is almost exact­ly the same as theirs, which means that our body chem­istry is also almost exact­ly the same as theirs. Since chim­panzees, like many oth­er apes, are main­ly fruit-eaters (fru­gi­vores), it stands to rea­son that they prob­a­bly thrive on a diet that con­tains a lot of fruc­tose, which is a sug­ar that is com­mon in fruit. How­ev­er, the fruc­tose that wild chim­panzees eat is dilut­ed with water and fiber and pack­aged along with plen­ty of oth­er nutri­ents, along with antiox­i­dants and oth­er good things.

Yes, you can make your­self sick by eat­ing too much sug­ar. How­ev­er, it would be dif­fi­cult for most peo­ple to get that much sug­ar from eat­ing fruit! One study found that eat­ing way too much added sug­ar (at least 25% of total calo­ries!) is asso­ci­at­ed with only a rel­a­tive­ly small increase in the amount of fat (triglyc­erides) in the blood and a small decrease in the lev­el of HDL (“good”) cho­les­terol. Of course, if you are hav­ing a prob­lem with triglyc­erides, you should prob­a­bly cut way back on your con­sump­tion of table sug­ar and high-fruc­tose corn syrup.

Sug­ar does rot your teeth, at least if you don’t brush care­ful­ly after meals. As a result, chim­panzees are prone to den­tal caries (cav­i­ties), just as humans are. How­ev­er, wild chim­panzees don’t seem to be fat and dia­bet­ic and they don’t get heart dis­ease. So why should I imag­ine that I would get fat and dia­bet­ic and suf­fer from heart dis­ease if I ate a lot of fruit?

Eat­ing lots of sug­ar does not cause dia­betes. Instead, cow’s milk seems to be the cul­prit in caus­ing type 1 dia­betes. A diet that is high in fats and ani­mal pro­tein seems to be the under­ly­ing cause in type 2 dia­betes.

Eat­ing too many calo­ries from any kind of diet tends to make peo­ple gain weight. How­ev­er, you gain a lot more weight from extra calo­ries from a fat­ty diet than from extra calo­ries from a high-car­bo­hy­drate, low-fat diet. Con­vert­ing sug­ar to fat wastes calo­ries. That’s why it’s hard to fat­ten on carbs but easy to fat­ten on fats.

Of course, there are a few peo­ple with genet­ic dis­or­ders that make it hard for them to tol­er­ate fruc­tose. One of them is hered­i­tary fruc­tose intol­er­ance. Anoth­er is fruc­tose mal­ab­sorp­tion.

Hered­i­tary fruc­tose intol­er­ance is a poten­tial­ly fatal genet­ic dis­or­der that occurs in about 1 out of 20,000 peo­ple in Euro­pean coun­tries. The dis­or­der results from the lack of an enzyme called aldolase B. In peo­ple with this dis­or­der, eat­ing any­thing con­tain­ing fruc­tose, includ­ing sucrose (table sug­ar), sets off a series of com­pli­cat­ed meta­bol­ic prob­lems that can ulti­mate­ly cause liv­er dam­age. The only solu­tion is for these peo­ple to avoid any foods that con­tain sucrose or fruc­tose.

Fruc­tose mal­ab­sorp­tion is an unre­lat­ed prob­lem that is far more com­mon but much less seri­ous than hered­i­tary fruc­tose intol­er­ance. Fruc­tose mal­ab­sorp­tion results from the absence of fruc­tose trans­porters in the cells that line the small intes­tine. With­out fruc­tose trans­porters, the per­son can­not absorb fruc­tose from his or her food. Even peo­ple who have some fruc­tose trans­porters might be able to absorb only a lim­it­ed amount of fruc­tose. The remain­ing fruc­tose will then remain inside the intestines, where it will be fer­ment­ed by bac­te­ria. The result is syn­drome that looks a lot like lac­tose intol­er­ance: gas and diar­rhea. Fruc­tose mal­ab­sorp­tion is a com­mon but often unde­tect­ed cause of recur­rent abdom­i­nal pain in chil­dren.

For­tu­nate­ly, I don’t have hered­i­tary fruc­tose intol­er­ance or fruc­tose mal­ab­sorp­tion. This means that I can eat as much fruit as I like!

Note: For a clear expla­na­tion of how the body han­dles sug­ar, see my book Thin Dia­betes, Fat Dia­betes: Pre­vent Type 1, Cure Type 2.

Behind Barbed Wire_Print

This Just In: Extra Calories Make People Gain Weight!

Eating More Fructose Than Nature Intended Is Also Probably a Bad Idea

I recent­ly read an arti­cle about a study that sup­pos­ed­ly found that high-fruc­tose corn syrup had a dif­fer­ent effect on the body than did “reg­u­lar sug­ar.” This made lit­tle sense, because high-fruc­tose corn syrup is only slight­ly high­er in fruc­tose than table sug­ar is. In fact, the study said exact­ly noth­ing about any dif­fer­ence between table sug­ar and high-fruc­tose corn syrup. On the oth­er hand, it did say that drink­ing a lot of sug­ar water can make you gain weight real­ly fast.

Dur­ing diges­tion, table sug­ar is rapid­ly bro­ken down to a 50:50 mix­ture of two sim­ple sug­ars: glu­cose and fruc­tose. High-fruc­tose corn syrup is a 45:55 mix­ture of glu­cose and fruc­tose. Not much dif­fer­ence. How­ev­er, the study wasn’t a com­par­i­son of high-fruc­tose corn syrup ver­sus what an ordi­nary per­son would think of as “reg­u­lar sug­ar,” it com­pared huge dos­es of pure fruc­tose to huge dos­es of pure glucose—a major dif­fer­ence.

In real­i­ty, the study showed three things. First, peo­ple can gain weight real­ly fast if they drink a huge amount of watery syrup, which pro­vides a lot of calo­ries while doing very lit­tle to sat­is­fy the appetite. Sec­ond, a calo­rie is a calo­rie. Peo­ple gain weight just as effec­tive­ly if they get extra calo­ries from fruc­tose or glu­cose. Third, fruc­tose has dif­fer­ent effects on the body’s metab­o­lism than glu­cose has, but we already knew that. None of these results were sur­pris­ing, so none of the find­ings of this study were actu­al­ly news­wor­thy to the gen­er­al pub­lic. The jour­nal­ists who wrote about this sto­ry made it sound news­wor­thy by mis­in­ter­pret­ing it.

Thanks to the mag­ic of the Inter­net and the Nation­al Library of Med­i­cine, I was able to find the actu­al arti­cle for myself. The sub­jects in the study first spent two weeks in a clin­i­cal research cen­ter, eat­ing “an ener­gy-bal­anced, high–complex car­bo­hy­drate (55%) diet.” Of course, 55% of calo­ries from com­plex car­bo­hy­drates isn’t “high” in com­plex car­bo­hy­drates by my stan­dards, but so what?

After spend­ing two weeks eat­ing the con­trolled diet, the sub­jects were sent home for an eight-week out­pa­tient study, in which they were allowed to eat what­ev­er they want­ed, as long as they drank enough of a sweet­ened bev­er­age to give them 25% of their calo­rie require­ments. Some of the sub­jects were giv­en a bev­er­age sweet­ened with pure fruc­tose (not high-fruc­tose corn syrup), the oth­ers were giv­en a bev­er­age sweet­ened with glu­cose.

As a result of guz­zling all that sug­ar water, the peo­ple in both groups took in more calo­ries than they need­ed. In fact, peo­ple in both groups took in rough­ly the same num­ber of extra calo­ries and gained rough­ly the same amount of extra weight as a result. That wasn’t sur­pris­ing, although it was inter­est­ing that the extra fat tend­ed to get deposit­ed in dif­fer­ent places, depend­ing on which kind of sug­ar was con­sumed. Nor was it sur­pris­ing that the fruc­tose bev­er­ages caused spikes in the amount of fat (triglyc­erides) in the blood after meals. Sci­en­tists already knew that fruc­tose does that. They’ve also known for decades that high lev­els of fat in the blood con­tribute to insulin resis­tance, which in fact occurred among the peo­ple who drank all that extra fruc­tose.

Although the study does sug­gest that eat­ing too much fruc­tose can be bad for you, it didn’t say any­thing about whether high-fruc­tose corn syrup was sig­nif­i­cant­ly worse than table sug­ar. In fact, a com­men­tary that accom­pa­nied the arti­cle said, “It is not known whether the adverse effects of sucrose and HFCS con­sump­tion are ‘dilut­ed’ by their low­er fruc­tose con­tent rel­a­tive to pure fruc­tose.” The com­men­tary does make it clear that if you are eat­ing too much fruc­tose, you prob­a­bly aren’t get­ting it from eat­ing too much fruit. “One would have to eat vast quan­ti­ties of fruits every day in order to ingest meta­bol­i­cal­ly adverse amounts of dietary fruc­tose.”

The take-home mes­sage for con­sumers wasn’t clear from the news accounts, but it’s very sim­ple. It’s hard to over­dose on fruc­tose from eat­ing fruit, but drink­ing syrup-water isn’t good for you.