Category Archives: Weight Loss

Time-Restricted Eating: Better to Restrict Earlier or Later in the Feeding Window?

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.

New Review of Fad Diets

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.

Tirzepatide for Weight Loss

The drug is not approved for infants

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.

QOTD: Dr Harriet Hall on Weight-Loss Pill Plenity

paleobetic diet, low-carb diet, diabetic diet
How ’bout this one?

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.

Is the Paleo Diet Best for Metabolic Syndrome?

I found a recent study involving the paleo diet at Clinical Nutrition ESPEN. I’m not paying for access to the full-text article until my book sales pick up. Access typically requires $30 USD.

Reference: Effect of Paleolithic-based low-carbohydrate vs. moderate-carbohydrate diets with portion-control and calorie-counting on CTRP6, asprosin and metabolic markers in adults with metabolic syndrome: A randomized clinical trial

Doesn’t that sound fascinating?

I’ve never even heard of CTRP6 and asprosin.

I miss the Oxford comma in the article title. You, too?

Click for a definition of metabolic syndrome.

The Iranian study at hand divided 80 folks into four different diet groups, to follow the prescribe diet for 10 weeks.

The Paleolithic low-carb diet “is defined as a diet consisting of 25-30% of energy from carbohydrate, 30% of energy from protein and 40-45% of energy from fat and encourages consumption of fruits, vegetables and lean meat.” There were two paleo diets: one involved calorie counting, the other portion control. All study subjects had metabolic syndrome.

This this is a mess already. And the experimental groups are tiny (20 subjects each). All diets were carbohydrate-restricted.

Results: A total of 69 participants aged 42.95 (9.27) with metabolic syndrome completed the trial. At the end of current 10-week dietary intervention trial, significant reduction in weight, waist circumference, body fat, visceral fat and waist-hip ratio (WHR) was observed in all four intervention arms (P < 0.001). Also, the observed differences among groups did not reach statistical significance (P > 0.05). Moreover, we found significant reduction in CTRP6 and leptin in all intervention groups (P < 0.001). Reduction of Asprosin level was also marginally significant between intervention groups (P < 0.05). All four intervention groups were found to improve cardiometabolic markers such as FBS [fasting blood sugar], TG [triglycerides], total cholesterol and LDL cholesterol compared to baseline. However, despite clinically significant difference, the within- and between-group changes were not statistically significant at the end of trial.

Conclusions: The current RCT [randomized controlled trial] in Iranian adults with metabolic syndrome revealed that both moderate and Paleolithic-based low carbohydrate diets with both delivery approaches have comparable beneficial effects in terms of body weight and composition, cardiometabolic factors and metabolism-related adipokines and hepatokines.

Abstract doesn’t mention calories provided (or recommended) the the four experimental diets! C’mon, man! In general, metabolic syndrome numbers improve short-term with sufficient caloric restriction regardless of the composition of the diet. E.g., eating nothing but water for five days will improve the metabolic syndrome numbers. But that’s no way to live.

I don’t know what to make of this study. But the eight researchers will undoubtedly put this article on their CVs.

Steve Parker, M.D.

PS: Here’s a low-carb paleo diet:

Semaglutide Versus Liraglutide: Which Is Better for Weight Loss?

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.

High Glycemic Load and High Glycemic Index Eating Linked to Weight Regain and Higher Blood Sugars

“Would you like a load?”

My headline says it all. Click for my definitions and discussion of glycemic load and glycemic index.

From Diabetes Care:

OBJECTIVE To examine longitudinal and dose-dependent associations of dietary glycemic index (GI), glycemic load (GL), and fiber with body weight and glycemic status during 3-year weight loss maintenance (WLM) in adults at high risk of type 2 diabetes.

RESEARCH DESIGN AND METHODS In this secondary analysis we used pooled data from the PREVention of diabetes through lifestyle Intervention and population studies in Europe and around the World (PREVIEW) randomized controlled trial, which was designed to test the effects of four diet and physical activity interventions. A total of 1,279 participants with overweight or obesity (age 25–70 years and BMI ≥25 kg ⋅ m−2) and prediabetes at baseline were included. We used multiadjusted linear mixed models with repeated measurements to assess longitudinal and dose-dependent associations by merging the participants into one group and dividing them into GI, GL, and fiber tertiles, respectively.

RESULTS In the available-case analysis, each 10-unit increment in GI was associated with a greater regain of weight (0.46 kg ⋅ year−1; 95% CI 0.23, 0.68; P < 0.001) and increase in HbA1c. Each 20-unit increment in GL was associated with a greater regain of weight (0.49 kg ⋅ year−1; 0.24, 0.75; P < 0.001) and increase in HbA1c. The associations of GI and GL with HbA1c were independent of weight change. Compared with those in the lowest tertiles, participants in the highest GI and GL tertiles had significantly greater weight regain and increases in HbA1c. Fiber was inversely associated with increases in waist circumference, but the associations with weight regain and glycemic status did not remain robust in different analyses.

CONCLUSIONS Dietary GI and GL were positively associated with weight regain and deteriorating glycemic status. Stronger evidence on the role of fiber is needed.

Steve Parker, M.D.

PS: The book below will help you keep your glycemic index and glycemic load low, thereby preventing weight regain.

Is the Paleo Diet the Easiest to Stick With?

I’ve never eaten rabbit, but would try it. A patient in Florida cooked squirrel for me. Tastes like chicken, as I recall.

An article at Public Health Nutrition suggests that, yes, the paleo diet is one of the last to be abandoned. I’m not paying the $35 for access to the full article, so I don’t know which diets were considered. I assume all the popular ones.


Objective: To use Internet search data to compare duration of compliance for various diets.

Design: Using a passive surveillance digital epidemiological approach, we estimated the average duration of diet compliance by examining monthly Internet searches for recipes related to popular diets. We fit a mathematical model to these data to estimate the time spent on a diet by new January dieters (NJD) and to estimate the percentage of dieters dropping out during the American winter holiday season between Thanksgiving and the end of December.

Setting: Internet searches in the USA for recipes related to popular diets over a 15-year period from 2004 to 2019.

Participants: Individuals in the USA performing Internet searches for recipes related to popular diets.

Results: All diets exhibited significant seasonality in recipe-related Internet searches, with sharp spikes every January followed by a decline in the number of searches and a further decline in the winter holiday season. The Paleo diet had the longest average compliance times among “new January dieters” (5.32 ± 0.68 weeks) and the lowest dropout during the winter holiday season (only 14 ± 3 % dropping out in December). The South Beach diet had the shortest compliance time among NJD (3.12 ± 0.64 weeks) and the highest dropout during the holiday season (33 ± 7 % dropping out in December).

Conclusions: The current study is the first of its kind to use passive surveillance data to compare the duration of adherence with different diets and underscores the potential usefulness of digital epidemiological approaches to understanding health behaviours.

Steve Parker, M.D.

Paleo Diet Reduced Body Fat and Waist Circumference

Paleolithic populations weren’t plagued by overweight and obesity

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.

During Maintenance of Weight Loss, Low-Carb Eating Allows You to Eat More…Calories

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.

Click pic to purchase book at E-book versions available at