Category Archives: Weight Loss

Chinese researchers reviewed the literature on time-restricted eating and metabolic effects on humans. I’m not paying $31.50 USD for the full text article, but here’s the abstract:

Time-restricted feeding (TRF), a feasible form of intermittent fasting, has been proven to benefit metabolic health in animal models and humans. TRF restricts the daily feeding window to 3 to 12 h for eating ad libitum, with fasting for the rest of the day. To our knowledge, specific guidance on the appropriate time period for eating during TRF has not yet been promoted. Therefore, the aim of the present review was to summarize the current literature on the effects of TRF with different eating windows in humans and compare their effects on metabolic health–related markers. Early TRF (which restricts food intake during the early period of the day) and delayed TRF (which restricts food intake during the later period of the day) studies have shown that both TRF regimens improve metabolic health in terms of reducing energy intake, decreasing body weight, improving insulin sensitivity, reducing blood pressure, and reducing oxidative stress. Differences between the consequences of early and delayed TRF were found, including differences in changes in blood lipid factors. These preliminary findings may help to provide guidance for choosing suitable eating windows during TRF. Future studies with rigorous designs and direct comparisons between the effects of TRF regimens with different eating windows on metabolic health markers are still needed.

Steve Parker, M.D.

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Frontiers In Nutrition in July, 2022, published “Fad Diets: Facts and Fiction.” Thank you, Frontiers, for making it available at no cost. The authors are based in Pakistan and Romania. They attempted to summarize the literature on popular fad diets. I am shocked that they included the Mediterranean diet as a fad. Read the article and 134 references then form your own opinion. Some snippets:

Regarding the Atkins Diet: “AD provides several benefits including weight reduction and cardio-metabolic health improvement, but limited evidence exists as compliance is the major barrier to this dietary regimen. Strict supervision by health professionals is advised as adverse metabolic sequelae can result from this type of diet.”

The Paleolithic Diet: “More randomized trials need to be done to highlight the consequences of such diets that eliminate one or more food groups. PD is powerful at advancing weight reduction for the time being but its efficacy in cardiovascular events is not well established as limited long-term data is available.”

Mediterranean Diet: “No evidence of adverse effects associated with MD is available in the literature. Rather, MD has preventive and therapeutic potential for many chronic diseases. It is highly suitable for the general public for the prevention of micronutrient deficiencies and specifically for those patients who are more health-conscious than just weight loss oriented.”

Vegetarian Diet: “No evidence of adverse effects associated with MD is available in the literature. Rather, MD has preventive and therapeutic potential for many chronic diseases. It is highly suitable for the general public for the prevention of micronutrient deficiencies and specifically for those patients who are more health-conscious than just weight loss oriented.”

Intermittent Fasting: “Despite the effectiveness of IF in weight loss as indicated by several studies, the current evidence is non-conclusive. The prime focus of available literature is weight loss but little is known about its sustainability and long-term health effects. More long-term trials should be conducted to draw a clear conclusion.”

Detox Diets: “Energy-restricted DDs are capable of short-term weight loss. But still, there is a high likelihood of health risks from detox products because of their nutritional inadequacy. As no convincing evidence exists in this domain so such diets and products need to be discouraged by health professionals and must be subjected to regulatory review and monitoring.”

Ketogenic Diet: difficult to summarize.

Steve Parker, M.D.

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Here’s the evidence at New England Journal of Medicine for tirzepatide for weight loss. It is a once-weekly injection. Cost? Unknown to me.

At baseline, the mean body weight was 104.8 kg, the mean BMI was 38.0, and 94.5% of participants had a BMI of 30 or higher. The mean percentage change in weight at week 72 was −15.0% (95% confidence interval [CI], −15.9 to −14.2) with 5-mg weekly doses of tirzepatide, −19.5% (95% CI, −20.4 to −18.5) with 10-mg doses, and −20.9% (95% CI, −21.8 to −19.9) with 15-mg doses and −3.1% (95% CI, −4.3 to −1.9) with placebo (P<0.001 for all comparisons with placebo). The percentage of participants who had weight reduction of 5% or more was 85% (95% CI, 82 to 89), 89% (95% CI, 86 to 92), and 91% (95% CI, 88 to 94) with 5 mg, 10 mg, and 15 mg of tirzepatide, respectively, and 35% (95% CI, 30 to 39) with placebo; 50% (95% CI, 46 to 54) and 57% (95% CI, 53 to 61) of participants in the 10-mg and 15-mg groups had a reduction in body weight of 20% or more, as compared with 3% (95% CI, 1 to 5) in the placebo group (P<0.001 for all comparisons with placebo).

Three to 7% of users stopped the drug due to side effects.

Click for a Diabetes Daily article about the drug.

Steve Parker, M.D.

PS: Let me help with weight loss.

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Dr Harriet Hall wrote a brief review of the new weight-loss drug Plenity at Science-Based Medicine. Her conclusion:

So far, effectiveness has been shown in only one placebo-controlled trial. Diet and exercise must be continued. It doesn’t work well for everyone: 6 out of 10 users lost at least 5% of their body weight; the other 4 didn’t. It appears to have fewer side effects than other weight loss products. Not a way to achieve ideal weight, but probably worth trying for patients who understand that it is only an aid and not a final solution. I hope they will be encouraged enough by a 22-pound weight loss to continue losing weight with or without Plenity.

Overweight and obese folks with diabetes also tend to lose weight with the new once-weekly injection therapy called tirzepatide, brand name Moujaro. (Where do they get these names?!) And remember that bariatric surgery is often very effective at weight loss and controlling diabetes…if you survive the operation.

Steve Parker, M.D.

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Semaglutide and liraglutide are drugs that were developed to treat diabetes and are FDA-approved for that. They are given by subcutaneous injection. Semaglutide is also FDA-approved for weight loss in non-diabetics if certain conditions are met.

Once-weekly semaglutide outperformed daily liraglutide in overweight and obese non-diabetics.

From JAMA Network:

Question Among adults with overweight or obesity without diabetes, what is the effect of once-weekly subcutaneous semaglutide, 2.4 mg, vs once-daily subcutaneous liraglutide, 3.0 mg, on weight loss when each is added to counseling for diet and physical activity?

Findings In this randomized clinical trial that included 338 participants, mean body weight change from baseline to 68 weeks was –15.8% with semaglutide vs –6.4% with liraglutide, a statistically significant difference.

Meaning Among adults with overweight or obesity without diabetes, once-weekly subcutaneous semaglutide, compared with once-daily subcutaneous liraglutide, added to counseling for diet and physical activity resulted in significantly greater weight loss at 68 weeks.

For prevention or improvement of overweight- and obesity-related illnesses, aim for loss of at least 5 to 10% of body weight. Assuming you’re overweight or obese in the first place. 16% body weight change is significant. 16% of 300 pounds (136 kg) would be 48 pounds (22 kg).

Steve Parker, M.D.

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An extremely small study of only seven healthy inactive experimental subjects (BMI 29.4. so almost obese, average age 32) found a drop in BMI to 27.7 but no change in the measured adipokines while following a paleo diet for eight weeks. The investigators write, “Adipokines are considered a class of biomarkers indicative of health and metabolic disease. They are secreted from adipose tissue and act in an autocrine, paracrine, or endocrine manner and have been implicated in the regulation of metabolic health and eating behaviors.”

Here’s a link to the full text article in International Journal of Exercise Science. The abstract:

The Paleolithic diet, characterized by an emphasis on hunter-gatherer type foods accompanied by an exclusion of grains, dairy products, and highly processed food items, is often promoted for weight loss and a reduction in cardiometabolic disease risk factors. Specific adipokines, such as adiponectin, omentin, nesfatin, and vaspin are reported to be dysregulated with obesity and may respond favorably to diet-induced fat loss. We aimed to evaluate the effects of an eight-week Paleolithic dietary intervention on circulating adiponectin, omentin, nesfatin, and vaspin in a cohort of physically inactive, but otherwise healthy adults.

Methods: Seven inactive adults participated in eight weeks of adherence to the Paleolithic Diet. Fasting blood samples, anthropometric, and body composition data were collected from each participant pre-and post-intervention. Serum adiponectin, omentin, nesfatin, and vaspin were measured. Results: After eight weeks of following the Paleolithic diet, there were reductions (p<0.05) in relative body fat (−4.4%), waist circumference (− 5.9 cm), and sum of skinfolds (−36.8 mm). No changes were observed in waist to hip ratio (WHR), or in adiponectin, omentin, and nesfatin (p>0.05), while serum vaspin levels for all participants were undetectable.

Conclusions: It is possible that although eight weeks resulted in modest body composition changes, short-term fat loss will not induce changes in adiponectin, omentin, and nesfatin in apparently healthy adults. Larger, long-term intervention studies that examine Paleolithic diet-induced changes across sex, body composition, and in populations with metabolic dysregulation are warranted.

Steve Parker, M.D.

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Low-Carb: Spaghetti squash “spaghetti” with meaty sauce

From The Journal of Nutrition:

In this analysis of a large feeding study, we observed higher estimated energy requirement on a low- compared with high-carbohydrate diet during weight-loss maintenance. The magnitude of this effect (about 200 to 300 kcal/d, or ∼50 kcal/d for every 10% decrease in carbohydrate as a proportion of total energy) and the numerical order across groups (Low-Carb > Moderate-Carb > High-Carb) are commensurate with previously reported changes in TEE [total energy expenditure], supporting the carbohydrate-insulin model.

Source: Energy Requirement Is Higher During Weight-Loss Maintenance in Adults Consuming a Low- Compared with High-Carbohydrate Diet | The Journal of Nutrition | Oxford Academic

In other words, in order to maintain weight loss, you have to (or can) eat more calories if you’re eating low-carb versus high-carb. If your chosen calories are expensive, this could be a drawback. On the other hand, many folks who lose weight complain that they just can’t eat very much or they’ll gain the weight right back. So, if they eat low-carb style, they CAN eat more……calories. Just not more Doritos and Ding-Dongs.

Steve Parker, M.D.

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