Prediabetes is one of the most common diagnoses in men over 35, and also one of the most ignored. It causes no symptoms, so most people who have it do not know. It is a real warning sign, but it is also one of the most reversible conditions in medicine: large trials show that moderate weight loss and regular exercise can sharply cut the chance of it turning into type 2 diabetes.
Key takeaways
- The American Diabetes Association (ADA) defines prediabetes as an HbA1c of 5.7–6.4% or a fasting glucose of 100–125 mg/dL.
- The ADA recommends testing all adults from age 35. Asian Americans should be tested from a BMI of 23, not 25.
- South Asian, Latino and other higher-risk groups develop diabetes at lower body weights and younger ages.
- In the US Diabetes Prevention Program, losing 7% of body weight and doing 150 minutes of activity a week cut the risk of developing diabetes by 58%.
- Strength training matters too. In a large study of US men, 150 minutes a week of weight training was linked to 34% lower diabetes risk.
- Vegetarian Indian diets can work very well for prediabetes if you watch refined grains, portion sizes and protein.
What prediabetes means
Prediabetes means your blood sugar is higher than normal but not yet in the diabetes range. Usually your body is becoming less responsive to insulin, the hormone that moves sugar from your blood into your muscles and liver. Your pancreas makes extra insulin to compensate, until eventually it cannot keep up.
It is common. In the US, the CDC’s national survey data estimate that 36.5% of adults have prediabetes, and only about 17% of them know it. In India, the ICMR-INDIAB national survey of over 113,000 adults found prediabetes in 15.3% and diabetes in 11.4%.
The ADA cut-offs
Doctors use three tests. Any one in the prediabetes range is enough for a diagnosis, though results are usually confirmed with a repeat test.
| Test | Normal | Prediabetes | Diabetes |
|---|---|---|---|
| HbA1c | Below 5.7% | 5.7–6.4% | 6.5% or higher |
| Fasting plasma glucose | Below 100 mg/dL | 100–125 mg/dL | 126 mg/dL or higher |
| 2-hour glucose (75 g OGTT) | Below 140 mg/dL | 140–199 mg/dL | 200 mg/dL or higher |
HbA1c reflects your average blood sugar over roughly the past three months and does not require fasting. Fasting glucose is a snapshot. The oral glucose tolerance test (OGTT) shows how well you handle a sugar load, and sometimes catches problems the other two miss. The World Health Organization uses a slightly higher fasting threshold of 110 mg/dL, so reports from different countries may differ.
Who should get tested, and when
The ADA’s screening criteria:
- Everyone: start testing at age 35. If results are normal, repeat at least every 3 years.
- Earlier, at any adult age: if your BMI is 25 or higher (23 or higher for Asian Americans) and you have at least one more risk factor. Risk factors include a parent or sibling with diabetes, high-risk ethnicity, high blood pressure, low HDL or high triglycerides, heart disease or physical inactivity.
- If you already have prediabetes: test every year.
The US Preventive Services Task Force recommends screening adults aged 35–70 with overweight or obesity. It advises considering earlier screening for Asian American, Hispanic/Latino, Black, Native American and Pacific Islander people, and for anyone with a family history of diabetes.
Why South Asian and Latino men face higher risk
If you are of Indian, Pakistani, Bangladeshi or Sri Lankan heritage, standard BMI cut-offs can give false reassurance. South Asian bodies tend to store more fat around the organs and less muscle at the same BMI. That is why the USPSTF notes a BMI of 23 may be the right cut-point for Asian Americans, and why the UK’s NICE uses 23 as the overweight threshold for South Asian and several other ethnic groups.
Latino adults also carry higher risk. CDC survey data put diagnosed diabetes at 13.0% in Hispanic adults, compared with 8.9% in non-Hispanic white adults. If you are an Indian man living in Latin America, or a Latino man with a family history, you have two good reasons to get tested early.
Waist size helps fill the gap BMI leaves. Keeping your waist under half your height is a simple target. Our guide to BMI vs body fat explains why.
What the Diabetes Prevention Program proved
The US Diabetes Prevention Program (DPP) enrolled 3,234 adults with overweight and prediabetes. One group followed an intensive lifestyle program with two goals: lose 7% of body weight and do 150 minutes of physical activity a week, mostly brisk walking. Another group took the diabetes drug metformin.
- The lifestyle group cut their risk of developing diabetes by 58%.
- In participants aged 60 and over, the reduction was 71%.
- Metformin cut risk by 31%.
The benefit held across ethnic groups and for both men and women. For a 90 kg man, 7% is about 6 kg: a realistic goal over six months.
India ran its own version. In the Indian Diabetes Prevention Programme, 531 Asian Indians with impaired glucose tolerance and an average BMI of about 26 were followed for three years. Lifestyle changes lowered the relative risk of diabetes by 28.5%, about the same as metformin. Combining both gave no extra benefit. The participants were not heavy by Western standards, which shows that lifestyle works even at modest body weights.
Your prediabetes action plan
1. Lose 5–10% of your body weight
The ADA’s nutrition guidance says losing 7–10% of body weight can help prevent progression to type 2 diabetes. Aim for a slow, steady loss while keeping protein high and lifting weights, so the weight you lose is fat rather than muscle. Our lose fat, keep muscle guide walks you through it.
2. Get 150 minutes of aerobic activity
Brisk walking was the main activity in the DPP. Spread it out: 30 minutes on five days, or shorter walks after meals. The ADA also advises breaking up long periods of sitting every 30 minutes with a few minutes of light movement. That matters for desk-bound professionals.
3. Lift weights two or three times a week
Muscle is your biggest store for blood sugar. In a study that followed 32,002 US men for 18 years, at least 150 minutes a week of weight training was linked to 34% lower diabetes risk. The same amount of aerobic exercise was linked to 52% lower risk, and doing both to 59% lower risk. This was an observational study, so it shows an association rather than proof, but it fits with what we know about muscle and glucose. Start with our guide to strength training after 35.
4. Fix your meal pattern
The ADA says there is no single best diet for prediabetes. Mediterranean, lower-carbohydrate and vegetarian or vegan eating patterns can all work. What they share:
- Plenty of non-starchy vegetables at most meals.
- Fewer refined grains and less added sugar. Cut sugary drinks, juices and sweetened chai or coffee first.
- Protein and fibre at each meal, which help you feel full and blunt blood sugar spikes.
- Whole foods over ultra-processed snacks.
5. Make vegetarian Indian food work for you
Plant-based eating can protect you, but quality matters. A Harvard study of over 200,000 health professionals found that a healthy plant-based diet (whole grains, vegetables, fruit, legumes, nuts) was linked to 34% lower risk of type 2 diabetes. A less healthy plant-based diet, high in refined grains, potatoes and sugary drinks, was linked to 16% higher risk.
That is the classic trap in many vegetarian Indian diets: large portions of white rice, rotis made from refined flour, fried snacks and sweets, with too little protein. A BMJ meta-analysis of more than 350,000 people found that each daily serving of white rice was linked to about 11% higher diabetes risk, with a stronger link in Asian populations who eat the most rice.
Practical swaps for an Indian vegetarian plate:
- Grains: keep rice or roti to about a quarter of the plate. Rotate in whole wheat, bajra, jowar, ragi, brown rice or quinoa.
- Protein: make dal, chana, rajma, sprouts, paneer, tofu, curd or eggs (if you eat them) a generous part of every meal. Our guide to protein after 35 has targets.
- Vegetables: fill half the plate with sabzi, salad or raita-based vegetables.
- Breakfast: swap poha or white bread for besan chilla, moong dal dosa, vegetable upma made with millets, or Greek yogurt with nuts.
- Snacks: roasted chana, nuts, fruit with curd instead of biscuits, namkeen or mithai.
- Drinks: unsweetened chai or coffee, buttermilk or water instead of sweet lassi, juices and soft drinks.
Vegetarians should also keep an eye on vitamin B12, especially if your doctor ever prescribes metformin, which can lower B12 levels over time. See our guide to vitamin B12 for vegetarians.
6. Sleep and stress
Short sleep and chronic stress make blood sugar harder to control and make it harder to stick with the steps above. Aim for 7–9 hours, and treat snoring with daytime sleepiness as a reason to see a doctor.
Safety note: See a doctor promptly if you have excessive thirst, frequent urination, unexplained weight loss, blurred vision or slow-healing wounds, which can be signs of diabetes. Whether medicine such as metformin is right for you is a decision for your doctor. If you already take glucose-lowering medicines, check with your doctor before big changes to diet or exercise, because low blood sugar is possible. Do not use home glucose meters or continuous glucose monitors to diagnose yourself.
How to track progress
- Repeat your HbA1c about every 3 months while you are making changes, or as your doctor advises, then yearly.
- Measure your waist monthly and weigh yourself weekly at the same time of day.
- Log your weekly minutes of walking or cardio and your strength sessions.
- Have your blood pressure and lipids checked too. Prediabetes often comes with other heart risks, as our heart health after 35 guide explains.
FAQ
Can prediabetes be reversed?
Many people bring their blood sugar back into the normal range with weight loss and exercise. Even if your numbers do not fully normalise, the DPP showed you can greatly lower your risk of progressing to diabetes.
I am slim but my HbA1c is 5.9%. How is that possible?
Body weight is only part of the picture. Genetics, ethnicity, low muscle mass, abdominal fat and inactivity all play a role, which is why South Asians can develop prediabetes at a normal BMI. Strength training and diet quality are especially important for you.
Do I have to give up rice and roti?
No. Reduce the portions, choose whole-grain versions more often, and pair them with dal, vegetables and protein. Low-carb or keto eating is one option, not a requirement. Our guide to keto and low-carb after 35 covers the trade-offs.
Is HbA1c or fasting glucose the better test?
Both are valid under ADA criteria and they sometimes disagree. Conditions that affect red blood cells, such as anaemia, can make HbA1c less reliable. Your doctor may use more than one test.
Should I take metformin for prediabetes?
Some doctors prescribe it for people at very high risk, but lifestyle change worked better in the US DPP. It is a personal decision to make with your doctor.
Free tools: check your waist-to-height ratio and find easy healthy food swaps for your everyday meals.
Sources
- American Diabetes Association. Standards of Care in Diabetes: screening criteria (Table 2.4)
- Johns Hopkins Diabetes Guide: Prediabetes categories (ADA criteria)
- USPSTF: Screening for prediabetes and type 2 diabetes
- NIDDK: Diabetes Prevention Program (archived)
- Ramachandran et al. The Indian Diabetes Prevention Programme. Diabetologia, 2006
- Harvard School of Public Health: Weight training linked to lower diabetes risk in men (2012)
- Harvard T.H. Chan School: Healthful plant-based diet and type 2 diabetes risk (PLOS Medicine, 2016)
- The Conversation: White rice and type 2 diabetes risk (BMJ meta-analysis, 2012)
- CDC: National Diabetes Statistics Report, detailed tables
- News-Medical: ICMR-INDIAB survey of metabolic diseases in India
- diaTribe: ADA nutrition guidance for diabetes and prediabetes
- AJMC: ADA recommendations on physical activity and exercise
This article is for general education and is not medical advice. Check with your doctor before starting a new training or nutrition plan, especially if you have a health condition.
