Low fat – another nail in the coffin

So here’s an interesting study: «Effects of a lifestyle intervention in metabolically benign and malign obesity.«

From the intro:

In the last few years it has been shown that metabolically healthy obese (MHO) individuals comprise roughly 30% of obese people and 10% of the adult general population [1– 5]. In addition to having insulin sensitivity that is similar to non-obese individuals, MHO individuals have lower liver fat content and lower intima media thickness (IMT) of the common carotid artery than obese insulin-resistant (OIR) individuals [6].

A group of German researchers put 262 non-diabetic people on a 9 month lifestyle intervention. The intervention was of the traditional (insane) type:

Counselling was aimed to reduce body weight by ≥5%, to reduce the intake of energy from fat to <30% and particularly the intake of saturated fat to ≤10% of energy consumed and to increase the intake of fibre to at least 15 g/4,184 kJ (1,000 kcal). Individuals were asked to perform at least 3 h of moderate sports per week. All participants completed a standardised self-administered and validated questionnaire to measure physical activity and a habitual physical activity score was calculated.

262 participants entered the study. Of these, 43 were normal weight and 116 were overweight. The remaining 106 were obese.

The point of the study was to see how this lifestyle intervention affected people with different insulin sensitivity (IS). The obese individuals were (BMI≥30.0 kg/m2) were grouped, based on their IS and IS was estimated from an oral glucose tolerance test (OGTT). Those with the best insulin sensitivity were labeled metabolically healthy obese (MHO, n=26) while those with poor IS were labeled obese insulin-resistant (n=77, OIR).

More from the intro:

Data about the effects of lifestyle modifications specifically in MHO and OIR populations are sparse: two small studies implemented energy-restriction diets for 12 weeks and 6 months in women [8, 9], and one a 6 month exercise intervention programme, also in women[10]. All three studies showed an improvement in cardiovascular risk profile in OIR, but not in MHO, women, despite similar weight loss [8–10].

So apparently traditional dieting does not do much for 70% the obese people. Anyway, weight loss was unimpressive as always with these strategies. The obese insulin resistant lost 3,3kg and the obese metabolically healthy lost a whopping 2,4kg of the average starting weight of 100kg. Remember this is 9 months of dieting. The difference between groups was not significant and the total body fat loss in the MHO didn’t even reach statistical significance.

However, fasting glucose (5.42 – 5.26 vs 5.07 – 5.17) and insulin (91.43 – 77.10 vs 38.33-39.70) both decreased more in the insulin resistant obese (there was a non-significant increase in both in MHO). This is perhaps not surprising as they had a much higher baseline level in both factors. Insulin sensitivity (OGTT) improved in the OIR group, but decreased (non-significant) in the MHO. Homeostatic model assessment (HOMA) also showed a decrese (2.98- 2.44) in the OIR group and an increase in the MHO group (1.16-1.23). Liver fat was high in the OIR and also decreased a bit in this group.

None of the cholesterol markers were interesting, but the authors noted that:

Unexpectedly, there was a small reduction in HDL-cholesterol levels in both groups. However, this was statistically not significant, indicating that these changes are not clinically relevant.

The end results show that despite a small weight loss, traditional calorie reduction can improve several markers of insulin resistance, but only if you are very resistant. And even though insulin sensitivity improved in the OIR group, their end level was still only 9,3 wheras the baseline level in the MHO group was 17,5.

The study illustrates that traditional lifestyle treatment only works (marginally) if your metabolism is really messed up. If not, there is little to gain from this strategy, and the study indicates that it might even make things worse. Though unfortunately not the final one, this is another nail in the coffin for traditional lifestyle treatment and a good reminder that overweight and obese people are a pretty heterogenic group that may respond quite differently to similar treatments. So don’t mess around with this nonsense. Go paleo instead.

The authors weren’t that impressed with the results either, writing:

«For MHO individuals, the option of a lifestyle intervention seems to be less effective if the target is to improve insulin sensitivity, although it may positively affect non-metabolic causes of morbidity and mortality in obesity, such as cancer and traumatic incidences. For OIR people, a lifestyle intervention clearly has positive effects. However, their insulin sensitivity remains very low even after the intervention compared with the MHO group, which indicates putative inadequate protection from type 2 diabetes and cardiovascular disease.«

And their solution to the problem? Drugs:

Thus, an early pharmacological treatment of obese insulin-resistant people, additional to the lifestyle intervention, may be considered as an appropriate therapeutic approach.

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