Time-Restricted Eating vs. Calorie Restriction for Weight Loss and Colorectal Cancer Risk Reduction

Overseen By Krista Varady, PhD

Age: 18+

Sex: Any

Trial Phase: Academic

Sponsor: University of Illinois at Chicago

Must not be taking: Weight loss, Anticoagulants, Antivirals, Immunosuppressants

Disqualifiers: Renal disease, Autoimmune disorders, Cancer, others

No Placebo Group All trial participants will receive the active study treatment (no placebo)

Compensation: Varies

Number of Visits: 3

Duration: 6 months

255 Participants Needed

What You Need to Know Before You Apply

What is the purpose of this trial?

This trial explores two eating strategies—time-restricted eating and calorie restriction—to help people lose weight and lower their risk of colorectal cancer. Time-restricted eating involves eating only within a specific time window each day, while calorie restriction (also known as dietary or energy restriction) focuses on reducing daily calorie intake. The trial compares these methods to determine which is more effective for weight loss and cancer risk reduction. Individuals who are obese, have a BMI between 30 and 49.99, and are current with colorectal cancer screenings might be good candidates for this trial. As an unphased trial, it offers participants the chance to contribute to important research that could lead to new insights in weight management and cancer prevention.

Will I have to stop taking my current medications?

The trial requires that you stop taking weight loss medications, anticoagulant medications, medications with endoscopic risk, antivirals, and immunosuppressant medications.

Is there any evidence suggesting that this trial's treatments are likely to be safe?

Research shows that time-restricted eating (TRE) is generally safe for most people. Studies indicate that it can aid in weight loss and improve overall health. Those who follow TRE often experience better body composition and lower blood pressure. However, one study found a possible increased risk of heart-related death with very short eating windows, less than 8 hours a day, suggesting caution with extremely short eating periods.

For calorie restriction (Cal-R), research has shown it is a safe method for adults with obesity to lose weight. Participants in Cal-R studies often experience weight loss and improved health indicators. Both TRE and Cal-R have been studied extensively, demonstrating they are well-tolerated options for managing weight. ^{1 2 3 4 5}

Why are researchers excited about this trial's treatments?

Researchers are excited about these treatments because they offer two unique approaches to weight loss and reducing colorectal cancer risk. Time-restricted eating (TRE) allows participants to eat freely within a set timeframe each day, which might align better with natural eating patterns and be easier to maintain than traditional diets. Calorie restriction (Cal-R), on the other hand, focuses on reducing daily calorie intake by 25% to promote weight loss. Both methods are distinct from standard diets that often require strict food types or intense calorie counting, and they may offer more sustainable, long-term health benefits.

What evidence suggests that this trial's treatments could be effective for weight loss and colorectal cancer risk reduction?

This trial will compare time-restricted eating (TRE) and calorie restriction (Cal-R) for weight loss and colorectal cancer risk reduction. Studies have shown that TRE, which involves eating only during certain hours each day, can help people with obesity manage their weight. However, some research suggests it might not be more effective for weight loss than eating throughout the day. In contrast, Cal-R, which involves consuming fewer calories, has consistently helped with weight loss, improved insulin use (a hormone that controls blood sugar), and reduced long-term inflammation. These changes are linked to a lower risk of colorectal cancer. Both methods show promise, but stronger evidence supports calorie restriction for weight loss and reducing cancer risk. ^{1 2 3 6 7}

Who Is on the Research Team?

Lisa Tussing-Humphreys, PhD, MS, RD

Principal Investigator

University of Illinois at Chicago

Are You a Good Fit for This Trial?

This trial is for adults aged 45-65 with obesity (BMI 30-49.99) who are prediabetic or insulin resistant, and those at elevated risk for colorectal cancer due to recent polyps. Participants must be up to date with CRC screening and not on any weight loss program, drug abuse, or have a history of certain diseases like renal disease or cancer treatment within the last year.

Inclusion Criteria

I am between 45 and 70 years old.

BMI 30-49.99 kg/m2

Are up to date with CRC screening

Exclusion Criteria

I have a history of serious health issues like kidney disease, autoimmune disorders, or severe heart and lung conditions.

I have been treated for cancer or have a genetic risk for colorectal cancer in the last year.

I am not on any weight loss medications.

Timeline for a Trial Participant

Screening

Participants are screened for eligibility to participate in the trial

2-4 weeks

Treatment

Participants are randomized into one of three groups: time-restricted eating, calorie restriction, or control, and undergo a 6-month intervention period.

6 months

Weekly visits for intervention adherence review

Maintenance

Participants maintain weight loss and continue monitoring for an additional 6 months.

6 months

Visits every 3 months for outcome measurements

Follow-up

Participants are monitored for safety and effectiveness after treatment

4 weeks

What Are the Treatments Tested in This Trial?

Interventions

• Calorie Restriction
• Time restricted eating

Trial Overview

The study compares two weight loss methods: daily calorie restriction versus time-restricted eating (a form of intermittent fasting), to see which is more effective in reducing body weight and lowering the risk markers for colorectal cancer in obese individuals.

How Is the Trial Designed?

Group I: Time Restricted Eating (TRE) Experimental Treatment 1 Intervention

During the active weight loss period, the TRE group will be instructed to eat ad libitum from 12:00pm - 8:00pm daily and fast from 8:00pm - 12:00pm. During the 8-h eating window, there will be no restrictions on types or quantities of foods consumed. During the fasting period, participants will be encouraged to drink plenty of water and may consume energy-free beverages, such as black tea or coffee. TRE subjects will meet with the TRE dietitian for 30 minutes at the start of the intervention to review instructions and goals, and then every week throughout the active weight loss period to review intervention adherence. At the beginning of the maintenance phase, total energy needs will be reassessed. Subjects will be instructed to main their body weight by consuming meals in an extended 10-h eating window every day and water fast between 8pm and 10 am, respectively.

Group II: Control Active Control 1 Intervention

Controls will be instructed to maintain their weight throughout the 12 m trial and to not change eating or physical activity habits. Controls will not receive dietary counseling. Controls will visit the research center every 3 months for outcome measurements.

Group III: Calorie Restriction (Cal-R) Active Control 1 Intervention

Cal-R subjects will be instructed to restrict energy intake by 25% of their baseline total energy expenditure (TEE) daily. Subjects will meet with a study dietitian for a 60-min one-on-one session to develop individualized weight loss meal plans to help them adhere to their calorie restriction goal. Meal plans will include portion sizes and food lists that are consistent with their food preferences and prescribed calorie levels for weight loss. Food scales will be provided to help with food portioning. Cal-R subjects will meet with the dietitian every week throughout the weight loss period to review intervention adherence and modify the meal plans as needed. Subjects will be asked to maintain their baseline level of physical activity. At the beginning of the weight maintenance phase, total energy needs will be reassessed.

Who Is Running the Clinical Trial?

University of Illinois at Chicago

Lead Sponsor

Trials

653

Recruited

1,574,000+

National Cancer Institute (NCI)

Collaborator

Trials

14,080

Recruited

41,180,000+

Published Research Related to This Trial

In a 12-week study involving 23 obese adults, time-restricted feeding (TRF) with an 8-hour eating window was found to be safe, as there were no significant changes in self-reported adverse events or disordered eating patterns.

The study suggests that TRF can effectively support weight loss in obese individuals without negatively impacting their health or body image perception.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Safety of 8-h time restricted feeding in adults with obesity. Gabel, K., Hoddy, KK., Varady, KA.[2019]

In a 12-week study involving 14 adults with obesity, time-restricted feeding (8-hour eating window) led to a significant weight loss of about 2 kg, indicating potential efficacy for weight management.

Despite the weight loss, the study found no significant changes in the diversity or composition of the gut microbiome, suggesting that time-restricted feeding may not impact gut health in terms of microbial diversity.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Effect of time restricted feeding on the gut microbiome in adults with obesity: A pilot study. Gabel, K., Marcell, J., Cares, K., et al.[2022]

Habitual continuous energy restriction (CER) has been shown to effectively prevent breast tumor formation in both animal studies and observational studies in women, while intermittent energy restriction (IER) and intermittent fasting (IF) may offer easier and potentially more effective alternatives for weight control and cancer prevention.

Animal studies suggest that IER and IF can reduce mammary tumor formation and may have different mechanisms of action compared to CER, including greater reductions in fat stores and improved insulin sensitivity, but more research is needed to directly compare these methods in humans.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Energy restriction and the prevention of breast cancer. Harvie, M., Howell, A.[2013]

Fasting for 4 days followed by refeeding in male Fisher 344 rats did not reduce the total number of aberrant crypt foci (ACF) in the colon, indicating that this dietary intervention may not prevent the early stages of colon cancer development.

However, the study found that the foci developed after fasting/feeding had a higher number of crypts, which is a significant predictor of tumor incidence, suggesting that fasting followed by refeeding could potentially enhance the risk of colon tumors.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Fasting/refeeding enhances the crypt multiplicity in rat colon carcinogenesis induced by azoxymethane. Premoselli, F., Sesca, E., Chiara, M., et al.[2013]

Time-restricted feeding (TRF) for 16 hours a day over four weeks led to a significant average weight loss of 2.6 kg in a pilot study involving 10 overweight, sedentary older adults, indicating its potential as a weight management strategy.

Participants also experienced clinically meaningful improvements in walking speed and quality of life, with high adherence rates (84%) and few reported adverse events, suggesting that TRF is a safe and feasible dietary approach for this population.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

The Effects of Time Restricted Feeding on Overweight, Older Adults: A Pilot Study. Anton, SD., Lee, SA., Donahoo, WT., et al.[2020]

Calorie restriction and its various forms, including intermittent fasting, show promise as potential adjuvant therapies for cancer by impacting tumor growth and metabolism, as supported by preclinical studies.

Preliminary clinical studies suggest that patients on reduced calorie diets may experience better outcomes and tolerance to chemotherapy and radiotherapy, indicating a beneficial role of calorie restriction in cancer treatment.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Calorie Restriction for Cancer Prevention and Therapy: Mechanisms, Expectations, and Efficacy. Vidoni, C., Ferraresi, A., Esposito, A., et al.[2022]

Energy restriction (ER) significantly reduced the total number of aberrant crypt foci (ACF) in male Fischer 344 rats, regardless of whether they were on a high-fat or low-fat diet, indicating a potential protective effect against colonic lesions.

The low-fat energy-restricted (LFER) diet was particularly effective, leading to fewer advanced ACF and tumors compared to the high-fat energy-restricted (HFER) diet, suggesting that dietary fat content plays a crucial role in modulating tumor development.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Energy restriction modulates the development of advanced preneoplastic lesions depending on the level of fat in the diet. Lasko, CM., Good, CK., Adam, J., et al.[2013]

Caloric restriction significantly reduces colonic cell proliferation (CCP), which is a marker for colon cancer risk, in both high-fat and low-fat diet groups of rats treated with a carcinogen.

While a high-fat diet did not increase CCP in the distal colon, it was associated with a higher tumor yield, indicating that dietary fat influences cancer risk differently than caloric intake.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Effects of caloric restriction and dietary fat on epithelial cell proliferation in rat colon. Steinbach, G., Kumar, SP., Reddy, BS., et al.[2013]

A 12-month randomized controlled trial will investigate the effects of time-restricted eating (TRE) and daily calorie restriction (Cal-R) on obesity and colorectal cancer (CRC) risk in 255 adults at increased risk for CRC.

Preliminary evidence suggests that TRE is safe and can lead to a weight loss of about 3% to 5%, along with improvements in metabolic health, but its specific effects on CRC prevention have not been rigorously tested before this study.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

The basis and design for time-restricted eating compared with daily calorie restriction for weight loss and colorectal cancer risk reduction trial (TRE-CRC trial). Gabel, K., Fitzgibbon, ML., Yazici, C., et al.[2023]

Caloric restriction and various forms of energy restriction, like intermittent fasting, have shown promising anti-cancer properties and may help prevent and treat colorectal cancer, which has a high mortality rate.

While energy restriction strategies appear beneficial, further research is needed to understand the optimal conditions for their effectiveness and safety in cancer treatment, particularly regarding diet composition and fasting duration.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Energy Restriction and Colorectal Cancer: A Call for Additional Research. Castejón, M., Plaza, A., Martinez-Romero, J., et al.[2020]

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