Health and Insurance Information

Fat Vs. Saccharide Overeating: Which Causes To A Greater Extent Than Fatty Gain?

Two human studies, published inward 1995 as well as 2000, tested the trial of saccharide vs. fatty overfeeding on trunk fatty gain inward humans.  What did they find, as well as why is it important?

We know that daily calorie intake has increased the US, inward parallel alongside the dramatic increment inward trunk fatness.  These excess calories look to have got come upwards from fat, carbohydrate, as well as poly peptide all at the same time (although saccharide increased the most).  Since the increment inward calories, carbohydrate, fat, as well as poly peptide all happened at the same time, how create nosotros know that the obesity epidemic was due to increased calorie intake as well as non exactly increased saccharide or fatty intake?  If our calorie intake had increased solely past times the improver of saccharide or fat, would nosotros live inward the midst of an obesity epidemic?

The best agency to answer this query is to examine the controlled studies that have got compared saccharide as well as fatty overfeeding inward humans.

Horton et al.

The starting fourth dimension study to address this query was published inward 1995 past times MD James Hill's grouping (1).  The championship of the newspaper is "Fat as well as Carbohydrate Overfeeding inward Humans: Different Effects on Energy Storage".  Sounds promising for the calorie skeptics.  Sixteen men (9 lean*, vii obese) were overfed past times 50 percent of calorie needs for fourteen days, past times adding excess fatty or saccharide to the diet.  After a four-week break, each individual was overfed the macronutrient they had non received the starting fourth dimension time (randomized crossover design).  Subjects were provided alongside all food, prepared inward a enquiry kitchen, although they were allowed to eat some of it at home.

After fourteen days, the researchers measured changes inward trunk weight, fatty mass, as well as thin mass.  Here's what they found:
There were no pregnant differences betwixt diets and/or groups inward trunk weight or trunk composition changes.  
Carbohydrate as well as fatty overfeeding caused nearly identical increases inward trunk weight, fatty mass, as well as thin mass, as well as this was truthful both inward the thin as well as obese groups.  Here's a graph of trunk weight changes:

And here's a graph of changes inward fatty mass:

Note that obese subjects seemed to gain to a greater extent than fatty than thin subjects.  This is presumably because they were overfed past times a greater absolute number of calories**.

If changes inward trunk fatness were essentially identical during fatty as well as saccharide overfeeding, why did the investigators select to soil inward the championship that "energy storage" differed betwixt macronutrients?  The argue is that saccharide overfeeding caused an increment inward saccharide burning as well as full release energy expenditure, spell fatty overfeeding had no pregnant trial on fatty burning or full release energy expenditure.  In other words, the trunk "burned off" some of the extra carbohydrate, but it didn't move off whatsoever of the extra fat.  A higher proportion of the fatty calories was stored every bit trunk fat.

Yet inward the end, the differences were small-- the trunk stored nearly all of the excess calories inward both cases, as well as whatsoever apparent differences inward release energy expenditure were non reflected inward fatty mass***.  Calorie-for-calorie, trunk fatty accumulation was around the same during fatty as well as saccharide overfeeding.

Lammert et al.

The instant study was published inward 2000 past times the enquiry grouping of MD Bjorn Quistorff (2).  Ten pairs of thin immature men were overfed past times v megajoules (1,195 kcal) per solar daytime for 21 days, given every bit either a carbohydrate-rich or a fat-rich diet****.  Subjects lived as well as ate inward a enquiry setting the entire time.  The study was extremely good controlled.

Body composition was determined weekly past times underwater weighing.  Increases inward trunk weight were similar betwixt groups, as well as increases inward fatty volume were nigh identical:

Interestingly, the carbohydrate-overfed grouping genuinely gained to a greater extent than thin volume than the fat-overfed group.  It's unclear to me whether that reflects actual tissue gain, or exactly increased glycogen storage.  Another interesting matter to banker's complaint is that fatty gain varied tremendously betwixt individuals.  Due to genetics, physical fitness, and/or other factors, some people exactly shop to a greater extent than trunk fatty when they eat excess calories, spell others move most of it off.  This has been confirmed repeatedly.

In whatsoever case, this study confirms that fatty gain is around the same whether people overeat fatty or carbohydrate.

Bonus Study: Hirsch et al.

We know that saccharide as well as fatty crusade around equal fatty gain per unit of measurement calorie during overfeeding, but what happens when people aren't overeating?  Does the proportion of calories supplied every bit fatty or saccharide impact trunk fatness inward that scenario?

The enquiry grouping of Drs. Rudy Leibel as well as Jules Hirsch kept a serial of subjects nether metabolic ward conditions, strictly controlling the diet as well as dramatically varying the proportion of saccharide to fat, spell keeping calories constant, for several months at a fourth dimension (3, 4).  Here's a summary of their findings:
We showed that the carbohydrate-to fatty ratio could vary widely alongside lilliputian or no alteration inward the release energy requirement for weight maintenance.  The results of a 13-week study inward which an private was fed a formula diet extremely rich inward saccharide as well as depression inward fatty for a menstruation of 38 d and, thereafter, for a longer time, a diet rich inward fatty as well as depression inward saccharide are shown inward Figure 1 [see below-- SG].  Weight varied lilliputian throughout the study as well as average release energy intake was the same throughout...  The argue for emphasizing these findings is that nether the strict weather condition imposed past times hospitalization as well as feedings of a formula diet, release energy needs are the same over long periods of fourth dimension fifty-fifty though carbohydrate-to-fat ratios vary.  Similar information were accumulated inward fifteen subjects.
Here, you lot tin privy encounter the weight trajectory of the adult woman described above:

Over a fairly long menstruation of time, her weight stayed inside a 1 kg range, despite huge differences inward diet composition.  The same matter was observed inward a number of other subjects.

In other words, nether non-overfeeding conditions, the saccharide as well as fatty content of the diet have got no measurable impact on trunk weight when calories are controlled.


There are ever caveats when interpreting scientific evidence.  Here are a few for today:
  • The studies nosotros discussed were small.
  • They may non have got been long plenty for differences to emerge.
  • The overfeeding studies didn't include women.
  • The overfeeding studies reported pregnant private variability.  In other words, some individuals may gain trunk fatty to a greater extent than readily when they overeat carbohydrate, spell others may live to a greater extent than sensitive to fat.  Or not.  We can't genuinely nation based on these studies, but it remains possible. 
Scientific evidence is never perfect, but at some request nosotros have got to create upwards one's heed which hypothesis is best supported.  In this case, the clear winner is the hypothesis that full calorie intake determines trunk fatness, but non the proportion of dietary fatty or carbohydrate.  

Based on the available evidence, the the States obesity epidemic in all probability resulted from an increment inward full calorie intake, non from changes inward fatty or saccharide intake that were acting independently of full calories.  We would probable live faced alongside the exact same obesity epidemic if our increased calorie intake came alone from fat, or alone from carbohydrate.

That beingness said, macronutrients (fat, carb, protein) are non irrelevant to trunk fatness!  They tin privy impact fatty storage past times affecting how many calories nosotros eat.  Added fats tend to increment calorie intake, spell high-protein diets tend to decrease calorie intake.  Of course, refined as well as processed versions of fatty as well as saccharide tend to favor higher calorie intake every bit well, due inward business office to higher calorie density as well as palatability.

Somewhat paradoxically, ane time a individual is overweight or obese, increasing the proportion of poly peptide as well as fatty at the expense of saccharide tin privy assist command appetite as well as cut down trunk fatness.  During moderate saccharide restriction, this trial seems to depend generally on increased poly peptide intake, but during to a greater extent than extreme saccharide restriction, at that topographic point may live a purpose for ketones.  I mean value at that topographic point are however mysteries hither that deserve farther scientific exploration.  

* Average trunk fatty per centum of thin grouping = 21.4%, which is non specially thin for a man.  BMI = 21.3, which is low, as well as therefore these people in all probability had a fairly undesirable trunk composition on average.  The investigators specifically excluded "highly trained individuals".

** Subjects received a 50% calorie excess.  Since obese people have got a higher baseline calorie expenditure than thin people (25% higher inward this study), the excess calories during overfeeding would live greater inward an absolute sense.

*** The investigators create soil that the trunk composition changes they measured were close the detection limit, given the brusk duration of overfeeding.  The subtext is that the fatty overfeeding grouping may have got ended upwards gaining a fight to a greater extent than fatty if the study had lasted longer.  Personally, I'm skeptical of this possibility, due to the nearly identical trunk composition changes they reported as well as the results of Lammert et al.

*** Carb-rich: 11%, 78%, 11% of calories every bit fat, carb, protein.  Fat-rich: 58%, 31%, 11% of calories every bit fat, carb, protein.  In the carb group, a lot of the calories came from refined saccharify (sucrose).


Post a Comment